Legal Status of Emulation

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This page will try and document some notable incidents regarding the legal status of emulation. Nothing in this page should be considered legal advice.

The downloading and distribution of ROMs in most jurisdictions is considered a violation of copyright laws, with the exception of ROMs licensed in the Public Domain or other licenses that allow distribution. This also applies to other copyrighted material such as BIOS files.

The legality of using encryption keys for emulators or accessing personal video collections is a debated topic. These keys, typically generated by random number algorithms, are not subject to copyright protection unlike creative content. In the realm of DVDs, Blu-rays, and HD DVDs, the question arises: should using open-source software to decode, watch, or back up your legally acquired video collection be restricted due to these non-copyrightable encryption keys?

There are even political parties, such as the Pirate Party UK, whose core policies focus on reforming copyright and patent laws[1], supporting privacy, reducing government and business surveillance, and championing freedom of speech and expression.

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Notable Legal Incidents[edit]


Direct legal action[edit]

1992 - Atari Games vs. Nintendo
Action: Pre-emptive lawsuit from Atari Games. Lawsuit against Atari Games for making new hardware copying the functionality of Nintendo's lock-out system, the 10NES, meant to prevent the NES from loading unauthorized game cartridges
Reason: Atari attempted to reverse-engineer 10NES, they got a leaked copy of the source code after lying to the US Copyright Office (!), and then replicated it to make new games. Nintendo sued for patent infringement, copyright infringement.
Outcome: Settlement, although the courts ruled in favor of "reverse-engineering being fair use" it was tainted by the copyright-infringing way Atari acquired the source code. Nintendo settled and shifted their legal strategy as it was embroiled in other lawsuits regarding its monopolistic behavior.
1994 - Game Genie vs. Nintendo
Action: Pre-emptive lawsuit from Galbo. Lawsuit.
Reason: Created an unauthorized NES dev kit. Nintendo argued that the Game Genie violated their intellectual property, infringing on their exclusive right to make derivative works of their copyrighted games. Nintendo relied on a precedent where a third-party company selling a speed-up kit for the Galaxian arcade game lost, but that was because the speed-up kit itself included copyrighted content from Galaxian.
Outcome: Nintendo lost. Deterred litigousness against third party publishers. Altering the output of video games was considered a case of "fair use". HOWEVER, they successfully lobbied for a similar law in Japan. As a result, devices that allow for cheating and patching them are outlawed there, with Konami going after people selling modified save files for Tokimeki Memorial in 1997. However, Nintendo's overly-aggressive actions against the doujin scene in 1999 triggered some public backlash that forced them to dial it down. Nintendo later collaborated with third party accessory publishers, but not for cheating devices.
February 1999 - UltraHLE (N64) vs. Nintendo
Action: Lawsuit against authors, Website Takedown
Reason: "Designed solely to play pirated copyright-infringing ROM copies"
Outcome: Discontinued project, developers killed their online presence, but the source leaked later in 2002 and was continued as UltraHLE 2064. Other better emulators appeared in the meanwhile.
Also notable for its time, UltraHLE was capable of playing commercial games while the Nintendo 64 was still commercially viable, a feat which was ultimately noticed by Nintendo. In February 1999, Nintendo began the process of filing a lawsuit against the emulator's authors, along with the website hosting the emulator. Speaking to PC Zone, Nintendo representative Beth Llewellwyn commented: "Nintendo is very disturbed that RealityMan and Epsilon have widely distributed a product designed solely to play infringing copies of copyrighted works developed by Nintendo and its third-party licensees. We are taking measures to further protect and enforce our intellectual property rights which, of course, includes the bringing of legal action." Despite this, UltraHLE had grown beyond either its authors' or Nintendo's control. Subsequently, Epsilon and RealityMan abandoned their pseudonyms and went silent.
2003 - GBA/LCD screen ghosting technique
Action: Nintendo patented a technique used by PocketNES, a NES emulator targeting GBA screens.
Reason: Nintendo was also developing their own NES emulation solution for GBA screens, the so-called overpriced Classic NES Series. They took the fan-developed technique and patented it.
Outcome: No action ever taken against the emulator,
June 2014 - GB/GBC/GBA Patents
Action: Patent for all GB/GBC/GBA emulators on all devices, for game-specific speed-hacks (using hashes)
Outcome: Not actionable (prior use), never used, expired
2023 - Dolphin (GameCube) / Valve vs. Nintendo
Action: Dolphin submission to Valve, in order to make it available there. Valve doesn't immediately approve it, and asks for Nintendo's feedback. Nintendo answer back, requesting a rejection from Valve.
Reason: Dolphin including AES keys in the code (deemed "circumventing DRM, breaching DMCA")
Outcome: Valve rejected Dolphin from Steam, with no further actions.
2024 - Yuzu (Switch) vs. Nintendo
Action: Lawsuit against the for-profit LLC that manages Yuzu and its Patreon
Reason: Emulation and personal backups itself (mentioned in passing), Encouraging and engaging in piracy of unreleased leaked games and prominently profiting off it, Yuzu not including AES keys but using them to load encrypted game images, using Nintendo imagery to promote their patreon. Comparisons presenting the emulator as the better alternative. Included guides for unlocking the protection of Switch hardware on the emulator website.
Outcome: Settlement. Both Citra (also under the same team and LLC) and Yuzu's online presence and development is discontinued. Tropic Haze was ordered to pay Nintendo $2.4m, retire from developing Yuzu or assisting Citra with development, issue statements denouncing emulation (in public) and claiming any emulation that deals with AES keys is illegal, and submit personal Switch hardware. See Yuzu#Lawsuit.
Also, roughly 8K repositories have been wiped[2][3].
suyu, a fork of yuzu continues from where that project left off on GitLab instead of Github suggested by the community due to potential takedown attempt. However, GitLab still took down the suyu repository due to the use of raw yuzu code. As a result, the suyu team use their own repository. Although their discord channel forced to shut down due to a court order[4], killing the project. Another fork of yuzu, Sudachi emulator discord channel shut down[5]. Provenance frontend received a DMCA takedown notice[6]. See Nintendo Switch emulators#Comparisons section.


2014-2015 - Dolphin (GameCube) / Project M vs. Nintendo
Action: The word "Project M" is bannable on the Miiverse. Had Twitch reject streams of the mod. Later in 2022, official tournament guidelines from Nintendo included "forbidden from using modified versions of Nintendo games". However, no DMCA was ever issued against the project.
Reason: Relies on emulation. Mod.
Outcome: Project M was abruptly shut down in 2015. The developers went on to develop their own fighting game.
2023 - Yuzu (Switch) / various Youtube channels vs. Nintendo
Action: Copyright take-down notices against videos promoting emulation of the Nintendo Switch for the following cases: Kotaku (game journalists) encouraging people to pirate leaked copies of Metroid Dread and Zelda Tears of the Kingdom after Nintendo denied them review copies (Nintendo of America took down the very video used in the article), Multiplayer mod for Zelda Breath of the Wild promoted on the Youtube channel of the mod author, and others.
Reason: Generic copyrighted audiovisual content DMCA justification (Game footage)
Outcome: No further retaliation from Nintendo against either Yuzu or the YouTube channels. Zelda Multiplayer mod shut down the project pre-emptively to avoid further trouble.

Technological measures[edit]

1994 - Super Nintendo Entertainment System
Select games trigger their anti-piracy without the proper save type, and actively try to mislead emulators and flashcarts. Worked around with SNES rom headers first, then a list of game-specific hacks.
2004 - Game Boy Advance
Select games (Classic NES Series, a series of $40 individual NES games on the GBA) go out of their way to detect emulator behavior and refuse to boot up.
Select games refuse to load without the proper save type, and actively try to mislead emulators and flashcarts. Worked around with a list of game-specific hacks.
2010 - DS
Select games (a Konami life-sim for example) check for memory read speeds and trigger lockouts.
2012 - Wii
Select games (late-gen Disney) actively check for emulator presence and refuses to boot-up. An ex-developer offered his assistance to the Dolphin team to work around the issue, but they refused it, citing clean room reverse engineering best practices.
2023 - Nintendo Switch
Irdeto (Denuvo, with a Sony stake) offered anti-emulation services to Nintendo third-parties. While Nintendo approved them as an authorized developer, no games yet made use of this.


In the meanwhile, Nintendo and its partners hired multiple emulation developers to help with official products. Starting all the way back in the early 2000s with the individual who helped with the iNES specification who was later involved in NES emulation on the GameCube, Game Boy Advance, e-Reader and the Virtual Console services. Nvidia (for the Nvidia Shield Chinese edition which included GameCube emulation) and NERD (for Nintendo Switch services and remasters) openly hired "emulator" developers.

Nintendo also offered bounties to people behind 3DS/Wii U/Switch exploits to disclose their exploits for them to patch, while suing others who chose to profit off it in ways they didn't approve off.


Nintendo developers clearly follow the emulation scene closely, as some updates were made to remove mentions of unofficial N64 memory setups they accidentally included, and leaks for NERD's GBA emulation on the Nintendo Switch clearly mentioned unofficial software. Oblique allusions by Miyamoto and other staff acknowledged how games like Star Fox 2 and Mother 3 were known about in the West, wondering whether is it "better off left that way". Some unofficial emulation artifacts used internally by Japanese Nintendo employees even made it accidentally to the product, and one Nintendo PR staff accidentally compared a Super Mario Maker level to a "romhack".

Similarly, multiple third-party publishers for Nintendo consoles openly use emulators developed from fan sources. This contrasts with the language used on their website that claims "all emulation is illegal". Although it's true that Nintendo used to reject some emulated collections (for Atari games) on the Nintendo DS, it's not clear whether it's out of an anti-emulation stance or unrelated quality control issues tied to the quality of the collection itself. Nintendo never went after third party publishers that made Nintendo-exclusives available on other consoles, neither did Sony the other way around, although that might be to avoid anti-competitive behavior and lawsuits with emulation.


Direct legal action[edit]

1999 - Bleem! (PS1) vs. Sony
Action: Lawsuit (lost, but crippling Bleem financially). Threats to retailers selling Bleem. Second lawsuit.
Reason: Paid Emulator. Unfair competition (runs on DreamCast and PC). Using Sony imagery to promote their product in print ads. Comparisons presenting the emulator as the better alternative. Circumvents/includes BIOS. Patent infringement.
Outcome: Sony lost the BIOS/unfair competition lawsuit for the PC version, however it was a pyrrhic victory for Bleem who went bankrupt soon after. The emulator was leaked afterwards. Some of the staff was hired by Sony to work on the official PS1 emulation for the PSP. Established a legal precedent.
1999 - Connectix VGS (PS1) vs. Sony
Action: Lawsuit.
Reason: Paid emulator. Copyright Infringement.
Outcome: Sony lost the lawsuit, but until then was awarded a temporary injunction that prevented the emulator's sale. Sony brought VGS and then discontinued it. Some of the staff was hired by Sony to work on the official PS1 emulation for the PSP. Established a legal precedent.
November 2017 - RPCS3 (PS3) / Patreon vs. Atlus
Action: DMCA takedown against the project Patreon
Reason: Circumvents DRM protections, promotes the availability of a specific game (Persona 5) on PC platforms, using Atlus imagery to promote their patreon
Outcome: No lawsuit or further action by Atlus, besides a damage control statement on their forums. Emulator development continued. After discussions with Patreon, all Persona 5 imagery was removed and its page in the compatibility list renamed to "[Untitled]" (later reverted) and the emulator developers treating that game's name like Voldemort for a while.

Atlus Games attempted a DMCA strike on the Patreon account used for the RPCS3 project. This was unusual because the PS3 was at the tail-end of its console generation, and Atlus was the one initiating the legal procedure rather than Sony. As it turns out, Persona 5 released in late 2016 and was commonly cited by Sony management as a very important exclusive. The game would never see release on either PC or other platforms until 2022, and Persona 5 marketing often encouraged fans of the game to buy a PlayStation 4 - a console struggling to sell in Japan back then. It's no surprise that Atlus (and possibly Sony) would be upset that PC users would settle for the emulated PS3 version instead. In their words: “The PS3 emulator itself is not infringing on our copyrights and trademarks; however, no version of the P5 game should be playable on this platform; and [the RPCS3] developers are infringing on our IP by making such games playable”.


Hired ex-Bleem/VGS staff for the PS1 emulation on PSP, and licensed a fan emulator for the PS Classic collector hardware.


While ambivalent towards emulators ever since they went third-party (except for the RPCS3 case, technically, as Atlus was under Sega at the time) that wasn't always the case.

Direct legal action[edit]

1993 - Sega vs. Accolade
Action: Lawsuit against a third-party cartridge developer and game developer.
Reason: Decompiled Sega's DRM to provide their own running copy, included Sega trademarks (the name, in Nintendo's case images) required for the game to work
Outcome: Sega lost. Decompilation of Sega's software, and the required trademark infringement to ensure interoperability, was considered "fair use", establishing a precedent for reverse-engineering in general, and emulation as a whole by proxy. Sega ultimately settled with Accolade and granted them publishing privileges.


While Nintendo and Sony sued the most successful PS1 emulators in the 5th Gen, Sega had a more novel idea to shut down Saturn emulation. GiriGiri is a proprietary Sega Saturn emulator and one of the first to run commercial games at a decent speed. The developer, MegaDeath, was hired by Sega and GiriGiri was made an official emulator under the CyberDisc service. The service only lasted a little over a year before it was shut down in early 2004.

Sega also provided an online service on the Dreamcast (exlusively in Japan) that offered emulated versions of Sega Genesis, Sega Master System, and NEC PC Engine games, years before the Wii Virtual Console. Only a single disc covering Sega Genesis emulation was released in the US, with leftover instructions on the disc by the developer addressed to people pirating the game and encouraging them to try other Sega Genesis games, including their proper compatibility settings.

Sega later collaborated with a huge number of fan emulation developers for their countless retro collections, both from Japan and elsewhere. Albeit some exclusive content was later on tampered with to prevent its compatibility with third-party emulators, to limit piracy and unauthorized resellers. Ex-Sega of Japan developers also worked on fan emulators. A lot of developer interviews by Sega developers discuss common emulation topics like input delay and CRT shaders and screen scales.

Related to emulation[edit]

Dumping tools, box art and other artwork stuff, magazines, screenshots, revivial projects, mods and hacks including fan-translations, Game engine recreations and source ports, homebrew, capturing and ripping home media and home video content (since VCR era) or media player software compatibility with optical discs encryptions including codec situations and Copy protection techniques since all of them are somewhat related to emulation, either directly or indirectly. The tension between copyright infringement and attempts to remove infringing content through the DMCA has been a longstanding issue, often hindering preservation efforts.


  • 2024 - WWE 2K24 has unbanned modder WhatsTheStatus following complaints from its community. WhatsTheStatus - who was banned for "violation of terms" - revealed on Twitter/X that, after speaking with 2K and the WWE team, they had "come to an agreement, and a fair one at that". Originally, 2K and/or developer Visual Concepts was unhappy with WhatsTheStatus' mods, saying that as they "negatively impact the game experience for other players", the modder was banned in order to ensure there is a "positive WWE 2K24 experience for all players".[7][8]


1983 - Atari, Inc. v. JS & a GROUP, INC.
Action: Atari, Inc. sued JS & a GROUP, INC. for contributory copyright infringement.
Reason: Contributory copyright infringement, implying JS & a GROUP's product (likely the PROM Blaster) enabled users to illegally copy Atari games.
Outcome: The district court decided that, as §117 had been rewritten based on input from the Final Report of the National Commission on New Technological Uses of Copyrighted Works (CONTU) that states that archival copies of digital media should be allowed “to guard against destruction or damage by mechanical or electrical failure,” and since game cartridges as media are not particularly subject to mechanical or electrical failure, making an archival copy of a game cartridge constituted copyright infringement.[9]


1983 - Apple Computer, Inc. v. Franklin Computer Corp.
Action: Apple Computer, Inc. sued Franklin Computer Corp.
Reason: Copyright infringement. Apple claimed that Franklin's Apple II compatible computers copied portions of Apple's operating system code.
Outcome: The court ruled in favor of Apple, establishing the following:
  • Copyrightability of software: Certain elements of computer operating systems are copyrightable.
  • This case was a landmark decision that significantly impacted software copyright law and the development of computer emulation.
  • The court's definition of fair use remains influential in software copyright cases today. Fair use: Compatible products can exist without infringing upon copyrighted material, as long as they meet the criteria of fair use.
  • Although not directly related to emulation, this case set a precedent that indirectly affects emulation by clarifying the legal boundaries of software compatibility and copyright protection, which are relevant to the creation and distribution of emulators.
  • Quite infamously, Apple hires anyone behind a promising iPhone emulator or compatibility layer, and it almost always gets shut down and scrubbed off the face of the Internet.
  • Apple used to have a really strict rule about emulators not being allowed on the App Store, however, there have been some recent developments suggesting a relaxation of this policy[10][11]. Although some of the developers from emulation community stated that the platform is still not attractive for emulators for various reasons[12][13][14][15][16], but for others it's good enough to release their projects[17][18][19][20][21][22][23]. Overall, there is some uncertainty about how the new App Store policies will affect emulators. Some developers believe that the new policies will make no difference, while others are more optimistic. It remains to be seen how Apple will interpret their own rules.


2021 - Caudel v.
Action: In April 2020, Amanda Caudel filed this putative class action against defendant, Inc. (Amazon)
Reason: Violation of California consumer laws by allowing customers to purchase electronic media content at a higher fee than rented content, when the purchased content might become unavailable to the consumer at a later date.
Outcome: The court grants defendant's motion to dismiss.

Bandai Namco[edit]

  • 2024 - Notice of Infringement[24].

Entertainment Software Association (ESA)[edit]

The Entertainment Software Association is the trade advocacy association for the US video game industry. Everyone who is anyone in game development and sales is a member. They own the ESRB rating system. They also were the organizers of E3. They've spearheaded prior attempts at taking down emulation sites. They were the ones who started the ball rolling against Pirate's Bay.[25] They've also lobbied against things such as banning loot boxes and right to repair legislation. Also lots of downloads taken down on by ESA's AI request.[26]

Internet Archive[edit]

Internet Archive Gets DMCA Exemption To Help Archive Vintage Software
In 2003 the Internet Archive, as part of research into vintage software archiving, discovered possible archiving issues involving the Digital Millenium Copyright Act. This could make it impossible to legally archive early computer software and games, even for accredited institutions wishing to store limited amounts of non-distributable, archival images. It's vital to make proper archival copies of these artefacts, because the life of magnetic media such as floppy discs has been estimated at 10 to 30 years.[27] Time is running out to properly archive much of this large body of work for safekeeping, to ensure it lives out its term of copyright and is available (in the short-term, under suitable copyright-constrained means) for posterity. With the aid of various exemptions[28], the Internet Archive is continuing its work with institutional and technical partners to research and archive this at-risk software, and would like to thank all those who worked hard to help us achieve our goal.
2023 - Hachette Book Group, Inc. v. Internet Archive[29]
Action: Hachette Book Group, along with Penguin Random House, HarperCollins, and Wiley, sued the Internet Archive in June 2020.
Reason: The publishers argued that the Internet Archive's programs, Open Library and National Emergency Library (NEL), infringed on their copyrights. The lawsuit focused on the practice of "controlled digital lending" (CDL) where the Archive scanned and lent digital copies of books from their collections, even if those books were still under copyright. The publishers argued this wasn't fair use and cut into their potential sales.
  • March 2023: The court ruled against the Internet Archive, finding CDL in this case wasn't protected by fair use.
  • August 2023: A negotiated settlement was reached. The Internet Archive agreed to stop lending digital copies of ebooks on which the publishers held copyright.
  • September 2023: The Internet Archive appealed the court's decision. The case is ongoing.
  • More than 500,000 books have been taken out of lending as a result of Hachette v. Internet Archive, the publishers’ lawsuit against our library, including more than 1,300 banned and challenged books.[30]
Internet Archive blog: What the Hachette v. Internet Archive Decision Means for Our Library


1984 - Sony Corp. of America v. Universal City Studios, Inc.
Action: Sony Corp. of America (defendant) was sued by Universal City Studios, Inc. (plaintiff)
Reason: Copyright infringement. Universal claimed that Sony's Betamax VCRs facilitated copyright infringement by allowing users to record and copy their copyrighted television broadcasts.
Outcome: The Supreme Court ruled in favor of Sony, establishing the following:
  • Non-infringing use: The Betamax VCR was not inherently infringing, as it had substantial non-infringing uses, such as timeshifting (recording programs to watch later).
  • Contributory infringement: The Court did not establish a strict standard for contributory infringement, but held that Sony could not be held liable for the infringing actions of its customers.
  • This case had a significant impact on the development of home video recording technology and the legal landscape surrounding copyright and new technologies.
  • The concept of "fair use" was not directly addressed in this case, but the Court's emphasis on non-infringing uses laid the groundwork for future fair use arguments related to new technologies.
  • While not directly about emulation, this case set a precedent regarding the potential liability of technology companies for the actions of their users, which has indirect implications for emulation and the legal discussion around emulators and copyright infringement.
See also Copy protection page.


Link's Awakening DX HD: A complete remake written in C# of the original 2D GBC game that was uploaded by an anonymous user to It featured widescreen support and the ability to scale the map, making it possible to view the entire map (with moving sprites) on one screen. It was online for roughly 4 days before it was inevitable taken down for including copyrighted assets, however the source code was included with the game and it has since been re-uploaded to various place. -
Portal 64: Original project taken down due to Nintendo's tools used for building the game for Nintendo 64, new one (Portal 64: Still Alive) aiming to remove the requirement on proprietary code.
  • A total of 379 fan-made games have been removed from gaming website and hosting service Game Jolt after Nintendo of America issued a mass DMCA takedown.[31]
  • Lots of ROM sites taken down by Nintendo. Funny thing is they allegedly downloaded and sold a rom back to customers[32]. In 2018, Nintendo vs LoveROMs - Verdict handed down, site owners ordered to pay $12m to Nintendo.[33] In the same year, EmuParadise has removed all ROMs from its website, effective immediately after the news of Nintendo filing a lawsuit against two similar sites, LoveROMs and LoveRETRO. The site is still available and you can visit it right now but without the benefit of being able to download many retro games, many of which came from Nintendo.[34] After emuparadise removed all the roms on their website in August, Romshepherd is closed. The site was already targeted by dns-blocking in August (at least from Italy) following a Nintendo legal initiative. Topcatroms, his brother torrent tracker faced the same destiny. Also 4chan removed the forum about emulators and Pleasuredome, a torrent tracker mainly focused on mame roms but also with console related content removed all the torrents with Nintendo stuff.[35] In 2019, Nintendo has won a lawsuit against a ROM-hosting website called RomUniverse.[36] Vimm's Lair has been asked to remove many games from The Vault on behalf of Nintendo, Sega, Lego, and the ESA. While most of these games (and the hardware to play them) haven't been sold in decades, ultimately it's their prerogative so these games are now gone for good, so in May 15, 2024 Nintendo of America has requested for 717 games and their images to be removed from Vimm - The Vault[37].
  • The Nintendo Power archive has been removed from Internet Archive even though there's no option to digitally buy issues of Nintendo Power since quite a long time.[38]
  • Lockpick_RCM and Kezplez-nx repositories taken down by Nintendo DMCA. [39][40]
  • Garry’s Mod is taking down (DMCA) decades of Nintendo-related add-ons[41][42]. Nintendo issues multiple DMCAs on the modding site 'GameBanana'.[43] Nintendo Takedown Wipes “Rhythm Heaven” Remix Tool & 250+ Forks Off GitHub.[44]
  • According to two separate community posts on YouTube, it seems like Nintendo is looking to take down fan-arranged sheet music based on its franchises. The first is via the popular channel Sheet Music Boss.[45] The second is from purpleschala, a pianist who has amassed a following of nearly 30,000. In a similar post, she confirms that her sheet music hosted via MusicNotes has been taken down by Nintendo, including arrangements for Fire Emblem and Xenoblade Chronicles.[46][47]


Various mod projects taken down by Rockstar.[48]

  • Flat2VR
  • Ozark
  • Vice Cry
  • OpenIV's Liberty City
  • Grand Theft Auto Underground
  • AI Powered GTA V: Story Mode with AI NPCs

Various Game engine recreations and source ports projects taken down by Rockstar's parent company.[49]

  • Re3
  • ReVC


  • 2017 - Microsoft bans game emulators from the Windows Store.[50]
  • 2023 - Microsoft cracked down on a loophole in the Xbox Store that allowed emulators to be downloaded and used on Xbox consoles to play older games, including many unavailable on Xbox consoles[51] and also bans gamers using Retail Mode Emulators on Xbox.[52]

Taito Corporation[edit]

  • In 2024, a DMCA takedown notice from Taito Corporation, targeting content on TeknoParrot servers.[53]



See also[edit]

External links[edit]