Install flightcrew by entering the following commands in the terminal:
sudo apt update sudo apt install flightcrew
Description:
C++ epub validator
FlightCrew is an epub validator written in C++. It is used by sigil to validate epub files, and may be generally useful for other epub creation utilities.
Homepage: http://code.google.com/p/flightcrew
Version: 0.7.2+dfsg-10
Section: universe/text