$ git clone -n https://src.fedoraproject.org/rpms/R-pdftools.git /var/lib/mock/f41-build-side-1-2645785-27204/root/chroot_tmpdir/scmroot/R-pdftools
Cloning into '/var/lib/mock/f41-build-side-1-2645785-27204/root/chroot_tmpdir/scmroot/R-pdftools'...
$ git fetch origin 494d5a7010b2707555d004ca78b6dfb358fd18e0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-pdftools
 * [new ref]         494d5a7010b2707555d004ca78b6dfb358fd18e0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 494d5a7 Disable bootstrap