It is interesting that people love json (now with schema), but hate XML while loving HTML at the same time. It is all pretty boring and largely the same imo.
true
versus 1
Some systems require the token "true", others will only treat 1 as the boolean true.For example, MS claims that for exchange ASD boolean values must be integer 1 or 0 [0], but then links to a W3C spec that allows for the tokens true and false [1]
At least with JSON and HTML, you don't need a separate definition file for basic, primitive data types.
[0] https://learn.microsoft.com/en-us/openspecs/exchange_server_...
[1] https://www.w3.org/TR/2004/REC-xmlschema-2-20041028/#boolean