Install libgmime-3.0-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libgmime-3.0-doc
Description:
MIME message parser and creator library - documentation
GMime provides a core library and set of utilities which may be used for the creation and parsing of messages using the Multipurpose Internet Mail Extension (MIME). . This package contains the documentation and examples of GMime.
Homepage: https://github.com/jstedfast/gmime/
Version: 3.2.0-1
Section: doc