Column Phone Type - Text Message - How is it used?

How is the Text message field used in the column type phone? Can’t seem to find any documentation on it.


I would suspect it’s a fixed message or a default initial message. Should be easy enough to test and find out.

I could not test it at all. It does not do anything when I touch text balloon other than turning on text messaging service if app is running at phone. If it is a browser it even does not do that even though I can make app use my phone to call the same number from the browser.
Can anyone help finding out what is this line used for.
thank you