CB Profile Pro is probably replacing that file so it can completely replace profile edit, profile view, and registration displays. All 3 of those have triggers though, but you can't completely replace their output. I've added a feature ticket to pass the $return by reference so those triggers can be used by CB Profile Pro to replace the output in CB 2.1 and won't need to modify core files anymore.
forge.joomlapolis.com/issues/6289