$ git clone -n https://src.fedoraproject.org/rpms/libsigc++30.git /var/lib/mock/f45-build-16971-494/root/chroot_tmpdir/scmroot/libsigc++30
Cloning into '/var/lib/mock/f45-build-16971-494/root/chroot_tmpdir/scmroot/libsigc++30'...
$ git fetch origin c4fc55834cafab72db6a445538b59fccb01a531a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libsigc++30
 * [new ref]         c4fc55834cafab72db6a445538b59fccb01a531a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c4fc558 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild