octave-doc 4.2.2-1build1.1 (amd64 binary) in ubuntu bionic

 Octave is a (mostly Matlab (R) compatible) high-level language, primarily
 intended for numerical computations. It provides a convenient command-line
 interface for solving linear and nonlinear problems numerically.
 .
 This package provides the following documentation in HTML, PDF and Info
 formats:
 - the main user manual
 - a document on the C++ classes used internally by Octave.
 .
 It also includes a reference card in PDF format and in a4, letter and legal
 paper sizes.
 .
 This package is required by the 'help -i' command at the Octave command-line
 and by the help documentation browser in the graphical interface.