XmHTML is a Motif widget capable of displaying HTML 3.2 documents.
Features include a very good HTML parser (which is as also available
as a Widget) with excellent document verification and repair
capabilities.

Features built in support for X11 bitmaps, pixmaps, GIF87a & GIF89a
(using a patent free LZW decoding method), animated gifs, JPEG
(baseline and progressive) and PNG (all features supported), anchor
highlighting, text justification, full HTML <FRAME> support, HTML
frames and many more. It also comes with four examples demonstrating
possible use of the XmHTML widget.

WWW: https://sourceforge.net/projects/xmhtml/