get_maintainer.pl gives you the list. Theres no equivalent in Firefox or Chromium to flag which Mozilla/Red Hat/Google/... manager does not consider your ticket an area of focus.
A kernel maintainer can completely ignore any submission with no repercussions even in principle. And they often do.
In Firefox, in my era at least, a reviewer who simply ignores a review request indefinitely was not doing their job and would get yelled at by someone --- me, if it came to my attention.
