The company said in a blog post that it had been able to reverse its decision after it received additional information about youtube-dl that made it possible to reverse a Digital Millennium Copyright Act takedown.
The script was taken down on 25 October following a complaint from the Recording Industry Association of America, a group of which Microsoft is also a member.
Folks, I needed this win. Little known context: youtube-dl is my origin story. It's the first project I worked on, and it got me into @recursecenter.— Filippo Valsorda ??❤️ ✊ (@FiloSottile) November 16, 2020
I haven't been involved in many years, but they still use a bit of hand-rolled RSA code I wrote for verifying self-updates ??? https://t.co/38htOLjF4B
The RIAA said at the time: "We have learned that your service is hosting the youtube-dl source code on its network at the following locations, among others (a list of URLs followed)."
"We note that the source code is described on GitHub as “a command-line program to download videos from YouTube.com and a few more sites."
After that, numerous people uploaded copies of the source code of youtube-dl to their GitHub accounts, leading to a warning from the company that they were hosting banned content on the site.
In the detailed blog post, issued on Monday, GitHub's Abby Vollmer said: "Most takedown notices we receive allege copyright infringement - that someone used their copyrighted work (often software code) in a way that infringes their rights.
"But as many people noticed, the youtube-dl takedown notice fell into a more unusual category: anticircumvention - an allegation that the code was designed to circumvent technical measures that control access or copying of copyrighted material, in violation of Section 1201 of the DMCA.
"Section 1201 dates back to the late 1990s and did not anticipate the various implications it has for software use today. As a result, Section 1201 makes it illegal to use or distribute technology (including source code) that bypasses technical measures that control access or copying of copyrighted works, even if that technology can be used in a way that would not be copyright infringement. Circumvention was the core claim in the youtube-dl takedown."
Vollmer added: "When we see it is possible to modify a project to remove allegedly infringing content, we give the owners a chance to fix problems before we take content down. If not, they can always respond to the notification disabling the repository and offer to make changes, or file a counter notice.
"That’s what happened in this case. First, we were able to reinstate a fork of youtube-dl after one of the fork owners applied a patch with changes in response to the notice.
"Then, after we received new information that showed the youtube-dl project does not in fact violate the DMCA‘s anti-circumvention prohibitions, we concluded that the allegations did not establish a violation of the law.
"In addition, the maintainer submitted a patch to the project addressing the allegations of infringement based on unit tests referencing copyrighted videos. Based on all of this, we reinstated the youtube-dl project and will be providing options for reinstatement to all of its forks."
Microsoft acquired GitHub in June 2018 for US$7.5 billion (A$9.79 billion) in Microsoft stock.