'hacking Tor' web page has a few problems
The page https://trac.torproject.org/projects/tor/wiki/doc/TorBrowser/Hacking#WaystoBuildTorBrowser for building just the browser has a couple of problems.
The first is that the origin/Master branch doesn't build using those instructions. The 'mach configure' line's first option throws an error. Remove that option and you get ValueError in build/moz.configure/init.configure split-triplet.
I went to branch tor-browser-68.5.0esr-9.5-1 and these went away. The page should point people to either 'oldest branch that builds' or just say use the latest if you're going to hack.
With this version, the steps are good except it misses one. It says that tor-launcher needs to be in browser/extensions. It doesn't say that torbutton needs to be in toolkit/torproject.
I know they are small, but they might save someone else some time.