While it is a standard 7-Zip archive, the "FCH" prefix often indicates it contains or plugin data for the FreeCommander software. Internal Structure of the Archive
Run the following command in a terminal to get a full listing of every file, its original size, and its compressed size: 7z l FCH.7z
l (List contents of archive) command. Lists contents of archive. Examples. 7z l archive.zip. lists all files from archive archive. 7zip.bugaco.com 7z - cheat/cheatsheets · GitHub
If you only need the list of names (useful for scripts), use: 7z l -ba FCH.7z l (List contents of archive) command - 7-Zip manual
These are the actual "chunks" of compressed data. Multiple small files are often grouped into a "solid" block to achieve higher compression.
To see exactly which files are inside FCH.7z without fully extracting them, you can use these methods:
The file is a compressed archive typically associated with FreeCommander , a popular file manager for Windows.