.FMPLUGIN File Extension
What is an FMPLUGIN file?
Plug-in used by FileMaker Pro, a desktop database program; contains compiled program code that adds functionality to the program; can add features such as custom data parsing, macros, or custom printing jobs.
FMPLUGIN files are actually folders. To view their contents manually, remove the ".fmplugin" file and open the resulting folder. FileMaker plug-ins are developed in C or C++ and must adhere to the FileMaker plugin specification.