For those who resonate with "why might this be useful", here are "plain git" alternatives to this tool:
searching for a function I deleted
git log -G someFunc
> quickly looking at a file on another branch to copy a line from itI use `git worktree` to "mount" long-running branches much to the same effect as Julias tool. To quickly look at a file from a non-mounted branch/commit, I use:
git show $REF:$FILENAME
> searching every branch for a function git log --all -G someFunc
Note that -G can be replaced with -F for a speedup if the pattern you are searching for is a fixed string.