I tried to be as consistent as possible with the list that already existed: 1. All entries were already lowercase, including those that should have caps (ie. Exception). @eht16 mentioned that PHP is case-insensitive. 2. The keywords list already contained more than "real keywords" (ie. unset, exception, etc.). I didn't introduce any new types; I just added missing values for identifiers that were already in the list: keywords, language constructs, errors/exceptions, fundamental constants, magic methods, interfaces/type hints.