Indesign - what does that hidden character mean?

I was just playing around with InDesign and XML when I noticed a hidden (nonprinting) character in my document. It consists of four dots, composing a rectangle:

(The nonprinting character above the h)

What does it mean? Note that the text containing this hidden character is part of an XML structure that I imported into InDesign.

(Additional question: Could I use this hidden character to somehow tell InDesign to automatically insert a hard wrap at that point?)