$ git clone -n https://src.fedoraproject.org/rpms/rust-mdbook-core.git /var/lib/mock/f45-build-43174-800/root/chroot_tmpdir/scmroot/rust-mdbook-core
Cloning into '/var/lib/mock/f45-build-43174-800/root/chroot_tmpdir/scmroot/rust-mdbook-core'...
$ git fetch origin f1c29701362c427f5c160271b773225bba91b6ba:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-mdbook-core
 * [new ref]         f1c29701362c427f5c160271b773225bba91b6ba -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f1c2970 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild