Apologies for the, in retrospect, somewhat lazy posting of an article with no comment. I thought that article had a section about how many of them allow single quotes if you don't "enable strict." I am not seeing it on review, though; so either I made that up in my mind, or I'm remembering another article. Either way, apologies.

I did find https://github.com/json5/json5 no a quick search that basically says what I asserted about people just jumping to another standard for things that you hand write. I was probably also thinking heavily about python's dict syntax. (And I confess, I still don't know when to use single versus double quotes in python...)