$ git clone -n https://src.fedoraproject.org/rpms/rust-uu_echo.git /var/lib/mock/f41-build-810804-146953/root/chroot_tmpdir/scmroot/rust-uu_echo
Cloning into '/var/lib/mock/f41-build-810804-146953/root/chroot_tmpdir/scmroot/rust-uu_echo'...
$ git fetch origin 240142cd1afa9a7ac500eb9c64c69d8ef0d2cf02:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-uu_echo
 * [new ref]         240142cd1afa9a7ac500eb9c64c69d8ef0d2cf02 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 240142c Rebuild with Rust 1.78 to fix incomplete debuginfo and backtraces