Is there an explanation of what the HUD Overlay does?
I see references in the community postings, but don't know what it actually does, or is supposed to do.
The HUD Overlay. is similar to what you see when pressing CMD+TAB on a mac (then all open apps appear in what's called a HUD Overlay). Or when you change volume, Mac shows the progress bar in a HUD Overlay.
In BTT you can create for example a button, which has "Show HUD Overlay when pressing Button" checked, and in there you can insert HUD Title and Text, this is what you will see displaying inside the HUD Overlay once you press that button on the TouchBar.
I could see a real use case, for example, to display a "copied" success message for a copy button, or whatever the like for visual "pop up" on screen
Exactly. It basically is a prepared message that pop ups on your screen and fades away all by itself.
You can use it to get confirmation if a script worked properly or not, or just give you feedback about the action you just triggered.
@Andreas_Hegenberg as a request, wouldn't it be nicer and maybe easier to understand for some users to transform the HUD to a macOS notification?
Thanks. I'll experiment a bit with the feature.
Hello! This is a great thread with some really awesome explanations.
I hope I can use it for an aditional query related to HUD workings.
Although I figured (more by hit-and-miss approach than by having become experienced) how to use JavaScripts to make some basic changes to the clipboard contents, I am unable to figure out how to script the HUD overlay so that it shows me the clipboard contents. Let me explain this further:
I would like to use clipboard manager to pull items from its history based on a keyboard shortcut. I am thinking of creating 3 triggers, all with the same keyboard shortcut, each assigned Paste Specific Items from Clipboard Manager. The only difference would be the "Paste items at position" value.
As a result of having several actions assigned to the same keyboard shortcut, when this shortcut is pressed, BTT first pops an overlay where it lets me choose which particular action I wish to trigger, and only once I pick an option, they it confirms with the HUD overlay Title/Detail Text.
The items in the list to choose from currently mirror the contents of the Notes field, for example, I populated the respective Notes fileds with "Paste 1st item from history", "Paste 2nd item from history" and "Paste 3rd item from history" and these three items are what I can see in the "initial overlay" or popup when I hit the shortcut. What I wish to achieve is that this popup shows the actual content of the clipboard on a specific position, so I know exactly which text "clipping" I'm choosing. Thing is, as this is not the HUD overlay but rather an additional popup which only shows up when there are more actions mapped to the same trigger, maybe it isn't even "scriptable" 
But even if that was the case, I'd still wish to know how to script the HUD overlay in the same way, should I choose to abandon the one-trigger-for-all history clipboard items solution.
I will appreciate greatly your help! 
I don't know if this will help you, but I do something similar in an "idiot way".
When I open the BTT Clipboard Manager, a floating menu also opens next to it. If I now press “3”, the third clipboard is pasted. The first 5 clipboards are enough for me. I could simply count, but it's easier with the large number next to them 
Hello Frank,
Thank you for the tip and for such a fast response! I am not sure how you managed to have that floating menu appear, is it a matter of some settings? If there wasn't any other way, this could be a nice alternative indeed.
But if it was at all possible, I'd rather avoid opening the clipboard manager as the window with all its complex interface somewhat breaks my flow. That's why I was hoping for keeping it minimalistic with the HUD overlay only 