[7][9][10][11][12] Prominent free software programs licensed under the GPL include the Linux kernel and the GNU Compiler Collection (GCC).

The GPLv2 was also modified to refer to the new name of the LGPL, but its version number remained the same, resulting in the original GPLv2 not being recognized by the Software Package Data Exchange (SPDX).

[33] Early drafts of GPLv3 also let licensors add an AGPL-like requirement that would have plugged a loophole in the GPL regarding application service providers.

However, there were concerns expressed about the administrative costs of checking code for the additional requirements in the GPLv3 drafts, and it was decided to keep the GPL and the AGPL license separated.

[36] Others, notably high-profile Linux kernel developers such as Linus Torvalds, Greg Kroah-Hartman, and Andrew Morton, commented to the mass media and made public statements about their objections to parts of the GPLv3 drafts.

[37] The kernel developers disapproved of GPLv3 draft clauses regarding DRM/tivoization, patents, and "additional restrictions", and warned of a Balkanisation of the "Open Source Universe".

The fifth section of the GPLv3 states that no GPL-licensed code shall be considered an effective "technical protection measure" as defined by Article 11 of the WIPO Copyright Treaty, and that those who convey the work waive all legal power to prohibit circumvention of the technical protection measure "to the extent such circumvention is effected by exercising rights under this License with respect to the covered work".

This means that users cannot be held liable for circumventing DRM implemented using GPLv3-licensed code under laws such as the US Digital Millennium Copyright Act (DMCA).

Because a GPL work is copyrighted, a licensee has no right to redistribute it, not even in modified form (barring fair use), except under the terms of the license.

Conversely, if one distributes copies of the work without abiding by the terms of the GPL (for instance, by keeping the source code secret), they can be sued by the original author under copyright law.

[57] Those who do not accept the GPL's terms and conditions do not have permission, under copyright law, to copy or distribute GPL-licensed software or derivative works.

Software developer Allison Randal argued that the GPLv3 as a license is unnecessarily confusing for lay readers, and could be simplified while retaining the same conditions and legal force.

We believe that a proper criterion depends both on the mechanism of communication (exec, pipes, rpc, function calls within a shared address space, etc.)

But if the semantics of the communication are intimate enough, exchanging complex internal data structures, that too could be a basis to consider the two parts as combined into a larger program.

[78] The remaining claims revolved around Project Monterey and were finally settled in November 2021 by IBM paying $14.25 million to the TSG (previously SCO) bankruptcy trustee.

[81] In May 2005, Daniel Wallace filed suit against the Free Software Foundation in the Southern District of Indiana, contending that the GPL is an illegal attempt to fix prices (at zero).

The suit was dismissed in March 2006, on the grounds that Wallace had failed to state a valid antitrust claim; the court noted that "the GPL encourages, rather than discourages, free competition and the distribution of computer operating systems, the benefits of which directly pass to consumers".

On 8 September 2005, the Seoul Central District Court ruled that the GPL was not material to a case dealing with trade secrets derived from GPL-licensed work.

[88] In 2011, it was noticed that GNU Emacs had been accidentally releasing some binaries without corresponding source code for two years, contrary to the intended spirit of the GPL, resulting in a copyright violation.

In the near future ChessBase will no longer sell products containing Stockfish code, while informing their customers of this fact with an appropriate notice on their web pages.

Examples of such companies include MySQL AB, Digia PLC (Qt framework, before 2011 from Nokia), Red Hat (Cygwin), and Riverbank Computing (PyQt).

It is possible to use the GPL for text documents (or more generally for all kinds of media) if it is clear what constitutes the source code (defined as "the preferred form of the work for making changes in it").

Ubuntu's app store does not demand any such requirement: "These terms do not limit or restrict your rights under any applicable open source software licenses.

[146][147] In response to Microsoft's attacks on the GPL, several prominent Free Software developers and advocates released a joint statement supporting the license.

[151] In 2001, the term received broader public attention when Craig Mundie, Microsoft Senior Vice President, described the GPL as being "viral".

"[162] Richard Stallman replied: "GPL is designed to ... ensure that every user of a program gets the essential freedoms—to run it, to study and change the source code, to redistribute copies, and to publish modified versions ... [Raymond] addresses the issue in terms of different goals and values—those of 'open source,' which do not include defending software users' freedom to share and change software.

[167] In 2014, dtrace developer and Joyent CTO Bryan Cantrill called the copyleft GPL a "Corporate Open Source Anti-pattern" by being "anti-collaborative" and recommended instead permissive software licenses.

[168] In September 2006, during the draft process of the GPLv3, several high-profile developers of the Linux kernel like Linus Torvalds, Greg Kroah-Hartman, and Andrew Morton, warned of a split in the FOSS community: "the release of GPLv3 portends the Balkanisation of the entire Open Source Universe upon which we rely.

[169] Following the GPLv3 release in 2007, some journalists[41][127][170] and Toybox developer Rob Landley[44][45] criticized that with the introduction of the GPLv3 the split between the open source and free software community became wider than ever because the significantly extended GPLv3 is essentially incompatible with the GPLv2.

He said, "I predict that one of the biggest success stories of GPLv3 will be the realization that the entire universe of free and open-source software can thus be combined into comprehensive open source solutions for customers worldwide.