I suspect the opposite will actually happen. The resulting Streisand effect will be a shot in the arm for youtube-dl or its immediate forks.
A fairly mundane scraping tool is now a fashionable "punk" project that will "stick it to the Man". Mirroring it is already an act of civil disobedience; developing it you can now explore some interesting problems in the space between the email-only world of Linux kernel development and the centralized Github/Gitlab model (i.e. do for issue-tracking what git did for merging). And it's likely simple enough (it's a python scraper, at the end of the day) that it can mobilize large swaths of developers.
Youtube-dl core developers should double-down on it, right now.
A fairly mundane scraping tool is now a fashionable "punk" project that will "stick it to the Man". Mirroring it is already an act of civil disobedience; developing it you can now explore some interesting problems in the space between the email-only world of Linux kernel development and the centralized Github/Gitlab model (i.e. do for issue-tracking what git did for merging). And it's likely simple enough (it's a python scraper, at the end of the day) that it can mobilize large swaths of developers.
Youtube-dl core developers should double-down on it, right now.