$ git clone -n https://src.fedoraproject.org/rpms/libsecp256k1-abc.git /var/lib/mock/f45-build-16939-493/root/chroot_tmpdir/scmroot/libsecp256k1-abc
Cloning into '/var/lib/mock/f45-build-16939-493/root/chroot_tmpdir/scmroot/libsecp256k1-abc'...
$ git fetch origin 9e66d9c8142711fe1ab6be814d07b1819cfe2ccf:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libsecp256k1-abc
 * [new ref]         9e66d9c8142711fe1ab6be814d07b1819cfe2ccf -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9e66d9c Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild