what are the consequences for working on a side project if it’s open-source? I get that if you work on it on company time, the company can demand any time spen

what are the consequences for working on a side project if it’s open-source? I get that if you work on it on company time, the company can demand any time spent from your wages. If you potentially put trade secrets into it they can ask for the work to be taken offline? But what if the work is open-source, you didn’t put any trade secrets (and can prove easily, e.g. it’s a different domain)? Maybe you worked on it during company time, maybe using company equipment. Can the company ask for it to be removed from the public? Moreover, what if you submit pull requests / contributions to existing open-source projects on company time? Surely the company can’t just take over the repo, who had no clue you were supposed to be working. But they can’t really “undo” the PR, even if they remove the exact code or even copyright the algorithm, because the information on how to implement it is already out there.