I want to be able to search page titles of all my open tabs in Firefox without installing yet another resource-consuming add-on to do so. Is this possible?
Yes, this is possible natively in Firefox.
In the address bar, simply prepend your search term with a % sign followed by a space:
Productivity geeks like myself can speed up this whole process by focusing the caret on the address bar with the shortcut CtrlL, and then typing