The feature for being able to override language prettification is good. But if a language is unknown, it seems to "just guess". Note the lower code sample when I specify
The color usage is nonsensical, and it looks a a lot better with no highlighting...which I can get by specifying
Whether this is a "bug" or a "feature request" is a matter of opinion. It's at least a bit lossy in my view, because at the moment of writing the post, the person might know the language (as is this case). They would rather it be prettified if supported, but
lang-none is their only alternative.
One "future proof" way is to agree on the
lang-XXX tags now, even for languages not currently supported by Google Code Prettify. Then if you use an unknown language, just fall back to monochrome text.
UPDATE: even better -- if for certain language tags the "guesser" could be selectively disabled, and then only turn on if you put in a language tag. It would be best to be off for everything in rebol by default and no need to put in these comments at all...