Found one file extension association related to EFM and 1 file format developed specifically for use with EFM.
Platform, operating system: Apple macOS / Mac OS X
Go to: EFM description
SourceForge software list & details
EFM works with the following file extensions:
Note: You can click on any file extension link from the list below, to view its detailed information. The list of extensions used or otherwise associated with the application may not be complete, because many common file extensions on our website, such as jpg (pictures) or txt (text files), can be opened by a large number of applications, or are too general file format. However most, if not all directly associated file extensions should be listed with its appropriate program. Although its likely, that some file extensions may be missing from the list of associated file extensions with the application, yet they can be opened, be part of, or otherwise be associated with the program.
EFM default file extension associations
Comparison table of actions that EFM can perform with its associated file type beta
This table might not contain all possible associated or supported file types or may contain incorrect data.
If you need more information please contact the developers of EFM (SourceForge.net), or check out their product website.
File type \ Action