$ git clone -n https://src.fedoraproject.org/rpms/vtk.git /var/lib/mock/f39-build-1874347-42728/root/chroot_tmpdir/scmroot/vtk
Cloning into '/var/lib/mock/f39-build-1874347-42728/root/chroot_tmpdir/scmroot/vtk'...
$ git fetch origin 5f9a1f7ae79797dc0650d77756b0ef008c749d11:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/vtk
 * [new ref]         5f9a1f7ae79797dc0650d77756b0ef008c749d11 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5f9a1f7 Fix -devel deps on netcdf-*-devel