$ git clone -n https://src.fedoraproject.org/rpms/R-bslib.git /var/lib/mock/f45-build-5994-345/root/chroot_tmpdir/scmroot/R-bslib
Cloning into '/var/lib/mock/f45-build-5994-345/root/chroot_tmpdir/scmroot/R-bslib'...
$ git fetch origin d74f34d4f1678f659eeb7526d1c0c8335fc26f9e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-bslib
 * [new ref]         d74f34d4f1678f659eeb7526d1c0c8335fc26f9e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d74f34d Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild