The endoscope is an inspection tool, and will enable you to see why the trunk won't open. You will use a screwdriver to engage the pneumatic release linkage, reposition the electric latch lock, or to press down on the latch release to open the trunk, depending on what you find.

Look on this site for a long thread entitled, "Trunk lid jammed"; You will find quite a few photographs of the latch mechanism, including pictures of what causes the trunk lid to refuse to open.