Install libxt-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libxt-doc
Description:
X11 toolkit intrinsics library (documentation)
libXt provides the X Toolkit Intrinsics, an abstract widget library upon which other toolkits are based. Xt is the basis for many toolkits, including the Athena widgets (Xaw), and LessTif (a Motif implementation). . This package contains the X Toolkit Intrinsics C API documentation.
Version: 1:1.1.5-1
Section: doc