Success!
And I am now successfully running a source install from git, which means I can pull changes
and rebuild extensions. I finally have fulfillment in life.
On a totally irrelevant note: the source install has access to the default system Qt theme, I guess, and boy is it ugly and blocky. That setting must've accidentally switched at some point
.
On a slightly less irrelevant note: exiting a setting in the Preferences appears to be called "Close without saving", whereas in the binary it was "Discard". I much prefer the former...