I think I've found the cause of the weird fonts used in the 7.4 docs.
The latest stylesheets (version 1.78) convert DocBook's <literal> to
HTML's <var>, which renders as italic proportional font in some/many
browsers. And there were some similar changes with less obvious
impact. I've fixed this in the current docs and the 7.4 branch and
filed a bug about it. Be sure to rebuild the docs for the 7.4.1
release and on the web site.