I removed an address from Broken links and it came back

Remove from the list only deletes the row, so the next visit to that address lists it again. That is right for a link you have fixed at the other end, and wrong for an address a bot keeps asking for.

Use Never list this again instead. It adds the address to Never list these addresses under Settings → Watching for broken links, and it stays off however often it is asked for. A line ending in there covers a whole section: /feed/ keeps /feed/x off and still lets /feedback through. To see an address again, delete its line, or run wp trrd unignore /the-address.

/* and / are refused there, because the first would hide every address and the home page is never listed anyway. The list holds 500 addresses. An address with a ?, a % or a space in it is kept written the way a browser sends it, such as /product%3Fid=5, so it hides only that address.

Adding a line, however it arrives (typed, from the button, or in an imported settings file), takes what it covers off Broken links straight away.

It only decides what Broken links writes down. Visitors see no difference.