This page reports exactly which published commit the web panel and the relay are each currently running, so you don't have to take the operator's word for it.
Clone it, check out the commit shown above, and run:
git archive e87649c4c336b04feb722bc9c22f392450d228d8 | sha256sum
If that matches the source hash above, the published source for this exact commit is what the hash corresponds to. This page cannot prove the running process was built from that checkout rather than something else entirely — it only makes that kind of claim specific and checkable instead of unverifiable.