@ferret If you have `aptitude` installed, you can search on the command line with

aptitude search "?installed ?depends(chromium|firefox|www-browser)"
aptitude search "?installed ?recommends(chromium|firefox|www-browser)"

(It can be done in one command, but the combination of "and"s and "or"s makes it awkward)

Or you can use the #aptitude TUI (run `aptitude` without options) to browse the dependency trees. `?` for help, `q` to quit.