7z code is a part of 7-Zip program distributed under the GNU LGPL. You can download 7-Zip sources and binaries from Download Page.
Since "CDMFISJLML" is a non-standard name, you should exercise caution before opening it. If you did not expect this file, follow these safety steps: CDMFISJLML.7z
A ".7z" file is a compressed container created by the archiver. It is highly efficient for: 7z code is a part of 7-Zip program
: It often makes files significantly smaller than the standard ".zip" format by using the LZMA algorithm. meaning if the file is password-protected
: Users can split massive files into smaller parts for easier sharing. Handling Unknown Files Safely
: It supports AES-256 encryption , meaning if the file is password-protected, the contents remain unreadable without the correct key.