> I hate encountering abandonware that is only obvious, because of the last modified date.

The date plus hundreds of issues, of which the last dozen are unaddressed variations of “is this project still alive”. And then you check the creator’s account and they’ve been active on other things. Just archive the repo. Please. It’s fine if you don’t want to work on the project anymore, that’s 100% your decision and your right, and no one should be able to criticise you for it. But please just do the tiny courtesy of letting other people know so an alternative can crop up and flourish. Archiving a repo takes less than a minute and is reversible if you ever change your mind.