I like avoiding duplicate bookmarks.
I guess, once installed, it will work without noticing.
So I tried to bookmark a site I already bookmarked, to see what happens.

"When at least one is found, it will remove the freshly created bookmark and show a notification about it"

The new bookmark was made and the old one is gone. I thougt it must be the other way.??

I don't know how to activate it, maybe it only works when adding new bookmarks? There is one thing i would like, I can't find it anywhere.

it is a bookmark addon that goes through all your bookmarks and tells you first which ones work and which ones don't, because some bookmarks I've had for more than 20 years and they don't work anymore, only going through 500+ is a hassle to remove individually.

Perhaps this could give option to auto search all bookmarks and in the background test them out to see if they are working or now malicious links instead. Testing if they not only work but if they are malicious links or not?

I like the app, but the pop-ups need to run in the background "or" in the sidebar. because I'm trying to do other things while it works, & its getting in the way.

I like the idea. Good!