If you need the latest in Inform 6 libraries and don’t mind the sting of using an unofficial archive, I’ve got the goods. Head on over to ftp.intaligo.com and use following login/password: email@example.com/whatever you like.
As far as its unofficial status, well, I got tired of waiting for others to fix their stuff. I’ve also added stuff to this archive that isn’t in the official archive — other I6 files that live on the web in various places that I’ve found useful. I’ll also be updating it on a regular basis, so enjoy!