Home Assistant hidden API?

I am playing around with building (NOT developing) my own light-weight HA front-end by utilising the HA Rest APIs.

I looked at the API Documentation here and quickly realised that there seems to be endpoints missing in that documentation.

For example I can access and even create automations using the following endpoint:
Yet, there is no documentation for that endpoint in the public API documentation.

Naturally I am wondering which other endpoint are available that aren’t documented.
Does anybody have that info and/or the un-redacted documentation?