I installed a TrueType font by running:
$ sudo gnome-font-viewer somefont.ttf
and clicking the "install" button.
I would now like to uninstall that font (as it seems malformed and makes programs crash when used), but I can't find where it has been installed on the filesystem.
If I run the above command again, there is an unclickable "installed" button where the "install" button used to be, but no option to un-install.
In hindsight I should have just put it in ~/.fonts but alas I did not.
I tried using font-manager, which does appear to have a "remove" button, but the font I installed does not appear there. It does appear in Gimp and Inkscape however, which is where it causes problems.
Best Answer
It turns out even though I ran it as root, it just installed it in
$HOME/.local/share/fonts/somefont.ttf(but owned by root), not system-wide (as I had expected).