How to disable Rouge syntax highlighting in Jekyll
Jekyll uses Rouge for syntax highlighting by default. If you want plain code blocks, or plan to handle highlighting another way, you can turn it off in _config.yml.
For a normal Jekyll site, add:
highlighter: none
GitHub Pages uses Jekyll with Kramdown, so use Kramdown’s syntax-highlighter option there:
markdown: kramdown
kramdown:
syntax_highlighter_opts:
disable: true
Restart the local Jekyll server after changing _config.yml; configuration changes are not always picked up while the server is running. Your fenced code blocks will remain in the page, but Rouge will no longer add syntax-highlighted markup.