Chosen source (syntax) highlighter, prettify, is no longer maintained.

[KhronosWebservices]

The included JS file run_prettify.min.js from CloudFlare is pointing to Google Code (https://google-code-prettify.googlecode.com/svn/loader/prettify.css). It appears that this JS library is archived and no longer maintained. If possible, this repository should move to a different JS library to handle the code prettifying.

[MarkCallow]

Transferring the issue to KTX-Specification. This is due to the value chosen for the :source-highlighter attribute in the KTX spec's Asciidoctor source: prettify. It is still functioning so is not a broken link even though perhaps not maintained.

The Asciidoctor replacement, highlight.js, is not giving as good results as prettify so I'll stick with it for now.