$ git clone -n https://src.fedoraproject.org/rpms/rust.git /var/lib/mock/f40-build-777865-129595/root/chroot_tmpdir/scmroot/rust
Cloning into '/var/lib/mock/f40-build-777865-129595/root/chroot_tmpdir/scmroot/rust'...
$ git fetch origin 89eacb88ce5a3dab18801af3055b466a310469e4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust
 * [new ref]         89eacb88ce5a3dab18801af3055b466a310469e4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 89eacb8 Update to 1.76.0.