$ git clone -n https://src.fedoraproject.org/rpms/asterisk.git /var/lib/mock/f42-build-863079-171404/root/chroot_tmpdir/scmroot/asterisk
Cloning into '/var/lib/mock/f42-build-863079-171404/root/chroot_tmpdir/scmroot/asterisk'...
$ git fetch origin 48f8731bc47681f16fe07ecaadf5152db9648c00:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/asterisk
 * [new ref]         48f8731bc47681f16fe07ecaadf5152db9648c00 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 48f8731 Rebuild for Jansson 2.14