In the documentation,it said maxLines configures maximum number of lines of text to display. The text will be truncated with an ellipsis if not all text is visible. Defaults to 0, which indicates no maximum.
I tried to utilize it on the secondary text of list template 1. I have more text than the screen can fit, or but it doesn't demonstrate 2 lines of text if i set the maxLines to 2,or truncate the text with an ellipsis when I set the line number to 1, neither does the authoring tool demonstrate any changes when I remove the maxLines attributes.
Source: amazon.com