SQLite Forum

JSON literals, how they work
And Wout, the API behind this is https://www.sqlite.org/c3ref/value_subtype.html

The value returned by the `json()` function is *tagged* as a JSON value,  
which another function can pickup and act upon. These subtypes are not visible  
or accessible when the value is returned to the statement, only the type is.

And AFAIK, there's no equivalent of `typeof()` for subtypes, although writing  
one would be easy, yet the returned integer wouldn't tell you much, it is  
basically an *opaque* thing meant for two (or more) cooperating functions  
to pass a modicum of information between them.