You forgot to mention XSLT, which is just such a ridiculously powerful tool when you got XML data. It allows one to transform XML into XHTML or even other formats. Edit: Browsers also support this automatically, so you open an XML document and you get to see a rendered HTML from it.

I had been tasked at least several times in my past jobs to develop XSLT scripts to transform data into user-readable content. I don't know of anyone that uses XSLT today and I have no idea if there is a JSON equivalent.