Does not support as many libraries as it could (unlike LocalCDN addon) and not updated with new ones, for many years now. Also not responding fast or at all to emails.

Sadly, out of date. LOCALCDN is a good/better alternative.

Did the job at one time, literally usuless since a year or more, but this kind of add-on is like LocalCDN or the ones that manage and erase cookies, they're gadgets.

Not many libraries support as I'd have liked.