$ git clone -n https://src.fedoraproject.org/rpms/copr-backend.git /var/lib/mock/f40-build-2478856-61610/root/chroot_tmpdir/scmroot/copr-backend
Cloning into '/var/lib/mock/f40-build-2478856-61610/root/chroot_tmpdir/scmroot/copr-backend'...
$ git fetch origin a6d8ec829b991aa2716c756ab0fadf08994d85a1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/copr-backend
 * [new ref]         a6d8ec829b991aa2716c756ab0fadf08994d85a1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a6d8ec8 Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild