$ git clone -n https://src.fedoraproject.org/rpms/rust-thiserror-impl.git /var/lib/mock/f45-build-45482-823/root/chroot_tmpdir/scmroot/rust-thiserror-impl
Cloning into '/var/lib/mock/f45-build-45482-823/root/chroot_tmpdir/scmroot/rust-thiserror-impl'...
$ git fetch origin d79ed67ad5f62ab1677100aca24c660c1eb29263:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-thiserror-impl
 * [new ref]         d79ed67ad5f62ab1677100aca24c660c1eb29263 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d79ed67 Update to version 2.0.20; Fixes RHBZ#2502118