I decided to start compiling my own again. I inadvertently downloaded, compiled and installed 8.99. For the first time I tried the ninja commands. It appears there is no uninstall included. I guess this is logical since things change.
Is it safe to just go in and delete the files under /user/local?
The important stuff like binaries are the same but you may have leftover nightly specific icons and shortcuts that live somewhere else if you just overwrite 8.0 install. Up to you if you care about it enough to find them and remove but generally in linux removing any user files is not “unsafe” and will not break anything unrelated.