$ git clone -n https://src.fedoraproject.org/rpms/libical.git /var/lib/mock/f39-build-1591894-38302/root/chroot_tmpdir/scmroot/libical
Cloning into '/var/lib/mock/f39-build-1591894-38302/root/chroot_tmpdir/scmroot/libical'...
$ git fetch origin 90d4dd7f89f0069714ef4fc14b2c102fe0301ec7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libical
 * [new ref]         90d4dd7f89f0069714ef4fc14b2c102fe0301ec7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 90d4dd7 Update to 3.0.17