Why does the structure need void *json member?

[jiangquantuan]

for example:
struct json_attitude { float roll; float yaw; float pitch; void *json; };
In the user's perspective, we don't know when to use void *json member in structure.In what scenarios do we need to use it?

[hanhui03]

void *json developer do not need to care, this is a variable used inside the jstruct functions.