Comment by kevincox
5 years ago
> Why are favicons cached separately?
Likely because they are used for bookmarks and you don't want clearing the cache to remove all of the icons from your bookmarks.
Of course you could only do this for URLs which are bookmarked however it would be more work (probably why it wasn't done) and would remove icons from your browser history (probably a minor loss).
TL;DR Because they are used outside the context of browsing.
why couldn't we solve that by having a separate cache for bookmarks sandboxed away from web content processes?
Presumptive user feedback: "How come when I click this bookmark which has the icon nice and right there it sometimes takes minutes for the icon to show up on the tab?"
Principle of least surprises for the user is probably at play here. Bookmarks and tab icons seem like reasonably similar "chrome" to the user.
Separating the caches isn't necessarily easy either: it is just as likely to hand the trackers at that point a good signal for people who bookmarked a site based on whatever heuristic ends up being to refresh that cache if it is no longer "recently accessed tabs".