I got curious, actually seems to check out and explains why it's so well documented (but also complex and oftentimes confusing):
> The first production release of Keycloak was in September 2014, with development having started about a year earlier.
https://en.wikipedia.org/wiki/Keycloak
https://github.com/keycloak/keycloak/releases/tag/1.0.0.Fina...
It's kind of cool to see a project successfully survive for so long.