I know Rule Machine detects and suppresses options that involve device types you don't have. How does one do that? I haven't seen that ability in the API docs that I can recall.
I'd rather avoid displaying a device picker whose options will be empty. Poor user experience.
This is not available to user apps (built-in apps can, but rarely do, take a look at all devices on your system--but one of those rare times is Rule Machine telling you what capabilities it supports for devices you don't have).
Hm, pity. I totally understand why apps only get access to devices the user has explicitly selected for them. But a Boolean anyDeviceHasCapability(capability) function on the system seems like a reasonable and useful thing to expose.
Maybe re-write it in more detail (desired outcome, use cases, etc...) and post it in the Feedback - Feature Requests area. Cannot hurt to try.
Will absolutely do that, but when I'm not on a phone. 
Download the Hubitat app
