It will only be deleted if the repo you fork from is a private repository. The documentation [1] covers the other scenarios, in all of which you keep your copy of the code (including when the public repository is made private later).
No, it doesn't. It only makes sense until you stop and go "Wait, no, hold on a minute. Why would they delete the fork instead of simply severing the fork relation in their fork relations table?".
You have access to many private company files. After you leave the company, the company is obligated to send you copies of all of the files because you may have linked to them. After all, you could have made personal copies of all of the files, so you should still retain access through links.
TIL, thanks! I probably confused this with the GitHub takedowns, when forks are removed as well (as it happened to the youtube-dl repo). I could imagine my manual clone not withstanding such takedown either, though.
This makes sense. Thank you for clarifying that important detail. It seems to be missing from the parts of the discussion I've read here.