Cool! I just added the DNS proof to my key. The web UI for validating them is pretty neat too.
On the orange site someone posted a link to the sample page https://metacode.biz/openpgp/key#0x6A957C9A9A9429F7 as well as the source: https://github.com/wiktor-k/openpgp-proofs#openpgp-proofs
Edit: reading through the docs it seems to add Lobste.rs as an identity provider the user JSON link should also return Access-Control-Allow-Origin: * HTTP header so that the JSON is readable from the web UI. Would that be something lobste.rs devs are willing to add?
Funnily enough, I know the person in the example; they showed it to me!