$ git clone -n https://src.fedoraproject.org/rpms/rust-idna.git /var/lib/mock/f39-build-2194742-51505/root/chroot_tmpdir/scmroot/rust-idna
Cloning into '/var/lib/mock/f39-build-2194742-51505/root/chroot_tmpdir/scmroot/rust-idna'...
$ git fetch origin 7d4e1db9d84a31fa489273064e9efadd1c003504:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-idna
 * [new ref]         7d4e1db9d84a31fa489273064e9efadd1c003504 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7d4e1db Update to version 0.5.0; Fixes RHBZ#2251085