License-free software

License-free software is computer software that is not explicitly in the public domain, but the software owner has not made explicit the terms of the license which makes the software fully copyright protected according to the Berne convention.

Examples of license-free software formerly included programs written by Daniel J. Bernstein, such as qmail, djbdns, daemontools, and ucspi-tcp. Bernstein held the copyright and distributed these works without license until 2007. From December 28, 2007 onwards, he started placing his software in the public domain with an explicit waiver statement.

Additionally, small scripts are frequently released without specifying a license. For example, the website Userscripts.org hosts more than 52,000 Greasemonkey user scripts, the majority of which have no specified license. Similarly, github reported in 2015 that 85% of the projects it hosts are unlicensed.

On his Software users' rights web page, Bernstein explains his belief that under the terms of copyright law itself software users are always allowed to modify software for their own personal use, regardless of license agreements. He says '"If you think you need a license from the copyright holder, you've been bamboozled by Microsoft. As long as you're not distributing the software, you have nothing to worry about."

He also says that software users are allowed to back up, to compile, and to run the software that they possess.

He further says that "since it's not copyright infringement for you to apply a patch, it's also not copyright infringement for someone to give you a patch," noting the case of Galoob v. Nintendo as precedent. Thus modified versions of license-free software can legally be distributed in source code form in whatever way that the original can, by distributing a patch alongside it.

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Wikipedia