[vineyardmike]

Considering you're a developer of a game called "team fortress" (based on your HN comment history) who had a domain for team fortress with WHOIS info updated in 2021, I'd say that its probably someone on your dev team trying to make a few bucks and knew the address. But maybe you registered this with Cloudflare and forgot, and Cloudflare is forwarding the email to you.

[drzel]

I have all those things, but I used a very specific email address for AWS.

Basically, [e-mail]

The unique_identifier is unique to this AWS account.

[nivertech]

Maybe you have a catch-all enabled in your email client?