I figured it out.
At least with respect to the DMCA notice.
And with respect to what they objected to.
And what youtube-dl.exe coders did.
Github seems to have taken youtube-dl.exe down, and then put it back after
tests were removed that the DMCA complained about and then Github put the
youtube-dl.exe pages back - but - to make it more confusing - as you
surmised, the youtube-dl.exe authors appear to have stopped development at
around that time point (I think).
This is what GitHub said:
"Today we reinstated youtube-dl, a popular project on GitHub, after we
received additional information about the project that enabled us to
reverse a Digital Millennium Copyright Act (DMCA) takedown. "
They linked this as that "additional information" that Github received.
That letter states, in part, the following explanation.
First, youtube-dl does not infringe or encourage the infringement of any
copyrighted works, and its references to copyrighted songs in its unit
tests are a fair use. Nevertheless, youtube-dl's maintainers are replacing
Second, youtube-dl does not violate Section 1201 of the DMCA because it
does not "circumvent" any technical protection measures on YouTube videos.
Similarly, the "signature" or "rolling cipher" mechanism employed by
YouTube does not prevent copying of videos.
youtube-dl Unit Tests Referencing Commercial Music
The RIAA's letter refers to a single file of youtube-dl's source code which
references several copyrighted songs. This file contains series of
automated tests that verify the functionality of youtube-dl for streaming
various types of video. The youtube-dl source code does not, of course,
contain copies of these songs or any others. And the presence of
several copyrighted song links in a large series of such tests does not
induce or encourage copyright infringement, for several reasons.
We hope this will clear the way for GitHub to reactivate the repository.