I do not believe this is fixable in ubuntu-meta at all, unless the Flavors want Firefox to be moved to desktop-common which would prevent any flavor from choosing chromium-browser. (Notably, Ubuntu Studio does choose Chromium instead of Firefox.)
Therefore, I'm closing the ubuntu-meta task and adding tasks for the flavors that don't ship the apt package.
I do not believe this is fixable in ubuntu-meta at all, unless the Flavors want Firefox to be moved to desktop-common which would prevent any flavor from choosing chromium-browser. (Notably, Ubuntu Studio does choose Chromium instead of Firefox.)
Therefore, I'm closing the ubuntu-meta task and adding tasks for the flavors that don't ship the apt package.