The interesting part of is this, to me, is:

what actually happened is that somebody reported the original upstream of this fork (WebMBro/WebMConverter) but since @WebMBro himself left a while ago (which prompted me to make this fork in the first place), GitHub couldn't get a response from him, so they shut down that repo along with all forks, with seemingly no communication towards other fork developers.

I had to contact GitHub myself in order to even get a notification of what was going on, and it took them about 3 days to restore any kind of access to my fork of the project.

One of the core guiding principles of open source has been, if you don't like it, fork it. Github made it easy to see where you forked it from, but apparently is pretty gung-ho to kill those forks without contacting them.