triptico.com is a Fediverse instance that uses the ActivityPub protocol. In other words, users at this host can communicate with people that use software like Mastodon, Pleroma, Friendica, etc. all around the world.
This server runs the snac software and there is no automatic sign-up process.
TIL about using pbpaste (on MacOS for example) to directly apply a git e-mail patch that is currently saved to your clipboard:
pbpaste | git apply
(Obviously doesn't carry over the submitters email/name etc, but for tiny changes it makes things easier than exporting mbox)