Make your files smaller by detection and removal of dead code.
Dead code means unnecessary, inoperative code that can be removed.
Dead code includes functions and sub-programs that are never called, properties that are never read or written, constants and enums that are never referenced. Dead variables are ones that are never read - even if they've been given a value. User-defined types can also be dead, and there may be a lot of extra API declarations. Even whole files can sometimes be completely unnecessary. The opposite of dead code is live, operational code.