On Firefox 32 (Ubuntu Gnome) things like the search icon, notification icon etc. do show a dotted outline, as do the main options on the dropdown menus. Where I have real problems is with the category badges - either on the forum homepage or the hamburger menu; they don’t show focus clearly (there is a partially aligned, blinking cursor; same for the “Reply” button at the bottom of this box.
@bluedreamer - most of the things you’ve mentioned can actually be triggered via keyboard shortcuts, which saves tabbing through the links. (? will bring up the shortcut menu, and there’s also a slightly more detailed breakdown in the “Cheat Sheet”.)