いえーい！
$ curl -s https://mastodon.zunda.ninja/.well-known/keybase-proof-config | jq .
{
"version": 1,
"domain": "mastodon.zunda.ninja",
"display_name": "zundon",
"username": {
"min": 1,
"max": 30,
"re": "[a-z0-9_]+([a-z0-9_.-]+[a-z0-9_]+)?"
},
"brand_color": "#282c37",
"logo": {
"svg_black": "https://mastodon.zunda.ninja/packs/media/images/logo_transparent_black-24a8608615e64fe9a08a898c25552819.svg",
"svg_full": "https://mastodon.zunda.ninja/packs/media/images/logo-fe5141d38a25f50068b4c69b77ca1ec8.svg"
},
"description": "Mastodon is a social network based on open web protocols and free, open-source software. It is decentralized like e-mail.",
"prefill_url": "https://mastodon.zunda.ninja/settings/identity_proofs/new?provider=keybase&provider_username=%{kb_username}&token=%{sig_hash}&user_agent=%{kb_ua}&username=%{username}",
"profile_url": "https://mastodon.zunda.ninja/@%{username}",
"check_url": "https://mastodon.zunda.ninja/api/proofs?provider=keybase&username=%{username}",
"check_path": [
"signatures"
],
"avatar_path": [
"avatar"
],
"contact": [
"zundan@gmail.com"
]
}