Install libfm-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libfm-doc
Description:
file management support (development documentation)
LibFM provides file management functions built on top of Glib/GIO, giving a convenient higher-level API. . This package contains the development HTML documentation.
Homepage: http://pcmanfm.sourceforge.net/
Version: 1.2.5-1ubuntu1
Section: universe/doc