MTA-STS policy configuration hosted on GitHub Pages.
We care about cybersecurity: if we expect people to trust us with confidential information, we need to ensure we're handling this securely - and not causing harm while we try to do good in the world.
We expect attacks involving emails to us ("inbound email") to be the most likely way we suffer a serious cybersecurity breach, based on an internal review of our processes and systems.
MTA-STS helps ensure inbound emails are encrypted: this prevents them being intercepted on their way to us. It's a standard defined by RFC 8461 and recommended by the UK's National Cyber Security Centre.
The standard involves hosting a file .well-known/mta-sts.txt that states we always want inbound email to be encrypted.
This repository specifically just hosts this file. It does so with GitHub Pages, which allows us to easily host static files that match the structure of this repository. Because GitHub Pages will serve everything, you can actually also find this file being served.
The standard also involves setting up various DNS records, which we do in Porkbun manually at the moment.