First, as a general rule, you can safely assume that, if we install a file, it IS required. Considering we install hundreds of .EXE and .DLL files, I don't think it's to be expected for support to reply to questions about the function of each one. Do you do that for all the software you install, which I'm sure comes with lots of .EXE and .DLL files as well ?
In any case, this is what they do:
Patcher.exe - does binary patching of files, for example to remove the default tow truck model or the default jetway model. Is used only by the installer, or by the GSX Control Panel to disable default jetways.
Tidy.exe - cleans up and reformat XML files, used to fix some problems with XML files being corrupted, either by other installers or by hand-editing. Used only at install time.
