This scenario addresses a common issue that users experience after upgrading.
After an upgrade you may see new areas in your Jomres pages, but instead of a string like "Advanced site config" you see something like _JOMRES_COM_ADVANCED_SITE_CONFIG.
Jomres allows different property types to have different language files, the language file is copied when the property type is created and put into a sub-directory in /jomres/languages. When you upgrade Jomres, those special language files aren't modified during the update therefore over time they'll start to miss language strings that appear in the Core files in /jomres/language.
New definitions are always added to the end of the language file, so you can copy the missing strings from the end of the Core language file into your special language file if you want to continue using the special language file.