Yeah, and it isn't like jq is being incorrect in this, the JSON RFCs recommend not using values that can't be represented as a 64 bit float (pasted links to a few RFCs in another response). So if you want to represent a large number safely, better to put it in a string, where special handling can be done after the initial JSON parse without loss of information.
And why should Qt be concerned with what jq can or can't do? If you're writing and reading back from Qt, the limitations of other implementations don't apply.
