given that the icecat add-ons wiki page is essentially un-maintained, there is one very simple way to improve the user-experience - the trisquel team maintains a catalog of add-ons, which is the default URL for the abrowser add-ons GUI - rather than packaging and maintaining add-ons, it is simply a curated list of known-free add-ons, each entry linking to direct downloads of .xpi files from mozilla - it would only be a matter of changing the default URL for the icecat add-ons GUI, to point to the triquel page:
https://trisquel.info/en/browser-plain that probably does not address the concern of thoroughly auditing them - given the large number of add-ons listed, its difficult to believe that anybody had the time to audit them properly - presumably they were accepted, based on the license stated on the mozilla web page (License: MIT -> its ok) - it does avoid having to package and publish them though, and satisfies the FSDG as well as the icecat wiki page does (assuming that the packages are licensed properly); because the web browser is not directed to the mozilla app-store
