$ git clone -n https://src.fedoraproject.org/rpms/perl-Devel-Size.git /var/lib/mock/f40-build-2239102-53595/root/chroot_tmpdir/scmroot/perl-Devel-Size
Cloning into '/var/lib/mock/f40-build-2239102-53595/root/chroot_tmpdir/scmroot/perl-Devel-Size'...
$ git fetch origin 2d71df768e326772cb4418ab45de40b27f2ffc5f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Devel-Size
 * [new ref]         2d71df768e326772cb4418ab45de40b27f2ffc5f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2d71df7 Package tests