v3.x: Does the Encoding Object's contentType allow whitespace around commas?

[handrews]

I expected it would (e.g. contentType: text/css, text/javascript, image/*) by analogy with the Accept header, while @ralfhandl read it more literally and expects only contentType: text/css,text/javascript,image/* would be allowed. I suppose it depends on your assumptions on the phrase "comma-separated list" which is all we say about it.