I just did. So which of those apps you’ve listed originally doesn’t predate October 2013 or isn’t made with JUCE or VSTGUI? Bitwig was in development since 2009 and Decent Sampler is JUCE plugin. Others are older.

Quoted from the same Wikipedia page: “In October 2013, Ecma International published the first edition of its JSON standard ECMA-404.”

All these apps predate first JSON standard, and now they are stuck with XML.