$ git clone -n https://src.fedoraproject.org/rpms/R-RCurl.git /var/lib/mock/f43-build-side-110352-58908425-6569187/root/chroot_tmpdir/scmroot/R-RCurl
Cloning into '/var/lib/mock/f43-build-side-110352-58908425-6569187/root/chroot_tmpdir/scmroot/R-RCurl'...
$ git fetch origin 2cc00dc4e2f5809323a0fcb2b7b368ebda27b6a0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-RCurl
 * [new ref]         2cc00dc4e2f5809323a0fcb2b7b368ebda27b6a0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2cc00dc R-maint-sig mass rebuild