Except for Suffixes.txt, each of these files consists of upper-case words in alphabetical order, one line to a word. Suffixes.txt is similar, but is arranged in reverse order of length. These files normally reside in the application directory, but may be overridden by identically-named files in a distinct working directory.
You can edit any of these lists temporarily in the "Ancillary lists" window. To make permanent changes, use a text editor such as Notepad.