If you press "edit", highlight the url, and then press the keys "alt f4" twice in a row, really quickly. You'll see some stuff pop up saying "Would you like to delete the existing url?" after you press it the first time. Sometimes it doesn't work and you gotta reload it and try again

Yeah I think you can hide threads, or convert them to drafts, to "delete" them. But as for actually deleting, you probably need a mod to do it.

i think you have to get a mod to do it for you
idk tho

I'm pretty sure that if you hover over it, there is a delete icon near an edit icon. Like how for me there is a remove icon next to the edit icon for this comment