$ git clone -n https://src.fedoraproject.org/rpms/rust-thiserror.git /var/lib/mock/f40-build-2170512-51021/root/chroot_tmpdir/scmroot/rust-thiserror
Cloning into '/var/lib/mock/f40-build-2170512-51021/root/chroot_tmpdir/scmroot/rust-thiserror'...
$ git fetch origin c77d9ccefabcbf36b6563b1f456460cf33b31119:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-thiserror
 * [new ref]         c77d9ccefabcbf36b6563b1f456460cf33b31119 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c77d9cc Update to version 1.0.52; Fixes RHBZ#2254781