What you're looking for indeed comes from the driver, in this case a custom command defined by the driver (others might be a "standard" command defined by a capability, which would have a predictable format--custom commands can vary).
While you could look at the driver code if it's open-source, you don't need to. Just look at the device detail page, specifically the "Commands" at the top. All the parameters will be listed, along with the expected data type and whether they are optional or required (asterisk). Hover your mouse over the command button, and you'll see:
If the device is what it appears to be (taking a wild guess based on the name of a single command), what you're seeing int he manual was probably written with HomeSeer's own hub in mind, if any. Most device manuals won't tell you much about Hubitat commands (most manuals are fairly platform agnostic, though theirs tend to be different given that they actually have a hub).
This almost always works! It just so happened that the one I was working with didn't distinguish between text and numeric in the the first field...and has a label (no highlight) of *ledNumber...but is a text field in the command. EVERYTHING else works perfectly...THANKS!