$ git clone -n https://src.fedoraproject.org/rpms/rust-polling.git /var/lib/mock/f40-build-2653425-66901/root/chroot_tmpdir/scmroot/rust-polling
Cloning into '/var/lib/mock/f40-build-2653425-66901/root/chroot_tmpdir/scmroot/rust-polling'...
$ git fetch origin 1302e1a795fe2ba82d314dd37eea973329b6e846:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-polling
 * [new ref]         1302e1a795fe2ba82d314dd37eea973329b6e846 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1302e1a Update to version 3.5.0; Fixes RHBZ#2262913