Can a condition compare two attributes? Where is documentation on 4.0?

Where is the detailed instructions for Rule 4.0? I am a newbie and can't find the instructions. Clicking help doesn't give very much info.

For local variables there is a "Connector". What is that?

If I want to create a condition that compares the room temperature to the setpoint of the thermostat, it seems to be then only way to do it is to set a variable to the room temperature and then compare the setpoint to that variable.

I am willing to read documentation but just can't find it.

Thanks for your help

https://docs.hubitat.com/index.php?title=Rule-4.0

To add do the docs above (also available in a forum post that may be nicer for inline screenshots and follow-up posts/questions):

This creates a device for a variable. The value of creating a device is that it can be displayed (or modified) on a Dashboard and used in "standard" apps (not just rules--Dashboard itself is an example of this), basically anything yo can do with a "regular' device. Before variables existed, some people actually created virtual devices to use in their place (e.g., a switch instead a boolean variable), so, if you're interested in a quick history lesson, this really just completes that circle in some sense. :smiley:

These exist for global variables, too, by the way.

This seem to be the case. I just tested since I wasn't sure, but apparently device-to-device comparisons have to use the same attribute on both sides of the comparison, so you can't do temperature versus a setpoint. There are lots of things that seem impossible but are in fact possible if you use variables (I'd use local if you don't have a reason not to), and this is one. So, good idea!