> The shell, perl and python are likely for scripting and not used during runtime.

Some git subcommands are implemented in these. git filter-branch is a shell script, git cvsimport is a Perl script, and git p4 (perforce interop) is a Python script. There are not too many left these days (git add -p/-i also used to call a Perl script), but they exist.

I'm sure you are aware, reading between the lines of what you said, why, but for some others who aren't aware of the history of git; it was originally about 50% C and 50% Perl, the performance critical parts were written in C and then various git commands were written in Perl. Over time almost all the Perl was removed because there were less Perl monks than C devs.

Now it would seem the logic is reversed; even though there are less Rust devs than C devs, Rust is going to replace C. Maybe now that git is large enough and entrenched enough such a move can be forced through.