I'm developing an addon that uses the History and since the favicons are not available I have to show some irrelevant random icons. If the favicons where available I could use the urls to fetch the proper one and display that. Are they not available due to some security risk?
The WebExtensions APIs were heavily modeled on Chrome's APIs. Occasionally new properties/methods are added, but not in this case.
I suspect that the team is so busy working on Manifest v3 compatibility that any request to provide site icon access will take a long time to be considered. But you certainly can try. I have an add-on that uses the topSites API, and Mozilla did add icon access to Chrome's API in that case: https://developer.mozilla.org/docs/Mozilla/Add-ons/WebExtensions/API/topSites/MostVisitedURL. So there is a precedent.
Thanks for the reply. I've seen this feature requested before by others. I think some rely on making network requests to get the favicons, very expensive. If the browser had an api to fetch the favicons by url from the browser it would be very useful. Right now what I do to show something is generate icons seeded by the urls, which is not that great since they're not recognizable as the actual favicons of the sites. Hope mozilla innovates here, FF addons already has stuff that chrome doesn't have, like tab warmup.