APA, RSView Development Project Archive (.apa)
The APA Developer file format
The APA format and files with the .apa extension are associated with the RSView Studio and RSView ME programs. These programs are used for software development. Projects that are created using the RSView programs save their projects in the APA format. These project files thus store all kinds of work-in-progress information for the software developed. The software in question is used to create Human-Machine-Interface (HMI) and control applications.
Technical details of APA files
APA files are, technically archive files that store project information. Thanks to the archiving, these project work-in-progress files can be shared among multiple computers where RSView Studio or similar programs by Rockwell Automation are installed. APA files are commonly found on Windows computers since RSView Studio and RSView ME are Windows-based programs. The file format is mostly deprecated by now since it was used to create applications on Windows 2000 and XP, Windows versions that have been replaced for some by now.