$ git clone -n https://src.fedoraproject.org/rpms/gnome-user-docs.git /var/lib/mock/f39-build-1465406-33579/root/chroot_tmpdir/scmroot/gnome-user-docs
Cloning into '/var/lib/mock/f39-build-1465406-33579/root/chroot_tmpdir/scmroot/gnome-user-docs'...
$ git fetch origin e5e0387deb0895d7a42d3e59d7afedab852fcad8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-user-docs
 * [new ref]         e5e0387deb0895d7a42d3e59d7afedab852fcad8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e5e0387 Update to 45.1