Tado TRV - what are all these entities..?

AKA: Noob: wow what are all these buttons!

I’m about a week into HA, and am still looking up the vertical learning curve with some anticipation.
I’ve had a Tado system running in the house for a couple of years with about 5 TRV.
on doing the whole autoconfigure businesss HA seems to have scooped up tonnes of stuff, but when looking in detail at each device, there’s a lot of entities I’m not really figuring out:

  • Heating - I’m guessing the amount of heat called for by the stat, or maybe the degree of openness of the valve?
  • Humidity - an environmental sensor
  • Link - state of it’s connected-ness to the gateway/controller?
  • Open window - I’m guessing a set of sensor conditions trigger this mode locally rather than offloading the decision process to the cloud?
  • Overlay - no idea - clues anyone?
  • Power - I’d have thought it would be the state of the device, however if a trv is reporting power = off, in which case I’d assume it was dead/flat battery…?
  • Tado mode - the home/away toggle, interesting that each trv has it’s own.
  • Temperature - another environmental sensor
    Early Start - this is a setting on the app, but it’s interesting that it’s also present on the device.

I appreciate I’ve a lot to learn about HA and all this, however there’s some interesting things on the above snapshot that I wouldn’t have expected, and also plain just don’t understand.

Can anyone point to any more resources for me to mug up on this stuff, or even just share their own experience and findings…?