$ git clone -n https://src.fedoraproject.org/rpms/pcg-cpp.git /var/lib/mock/f45-build-21459-584/root/chroot_tmpdir/scmroot/pcg-cpp
Cloning into '/var/lib/mock/f45-build-21459-584/root/chroot_tmpdir/scmroot/pcg-cpp'...
$ git fetch origin f4938920339074b6c11654a7a9fd4c39dbc048b3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/pcg-cpp
 * [new ref]         f4938920339074b6c11654a7a9fd4c39dbc048b3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f493892 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild