The project file (.xpj) is XML-based. You can open project files with the .mpj extension, the format for older versions of RoboHelp, but they convert to XPJ files.
Each project folder has an FPJ file that lists the folder contents. RoboHelp displays only those subfolders and topics that are listed in the FPJ file of a folder.
All the subfolders have their respective FPJ files. The name of an FPJ file except the FPJ file for the project folder is same as that of the folder.
The name of the FPJ file for the project folder is root.fpj. The root.fpj file is modified if you add, delete, or rename a topic or subfolder inside the respective folder. The root.fpj file is also modified if the order of topics or subfolders is changed in Project Manager.
A single-source layout file (SSL) is used for each single-source layout. An SSL file stores the properties of the respective single-source layout and is modified when you edit the properties. An SSL file does not get modified on generating, viewing, or publishing a single-source layout.
The following components have corresponding APJ files, which get modified when you edit the components:
•Conditional build tags
•Pop-up note topics
•See Also keywords
•Skins (when adding or removing skins only)
•Single-source layouts (when adding or removing single-source layouts only)
•Topic templates (when adding or removing single-source layouts only)
When you modify the following components, the respective file gets modified:
•Browse sequences (BRS)
•Image and multimedia files (filename extension varies)
•Style sheets (CSS)