WARNING: This page is about a different car, the 2015 Chevrolet Trax and 2015 Buick Encore. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Child Seat Bracket Access Hole Cover
Courtesy of GENERAL MOTORS COMPANY
Callout
Component Name
1
Child Seat Bracket Trim Cover Procedure Use a flat bladed tool to push the tabs inward to release the cover from the seat back.