This specification defines the QUERY method for HTTP.
A QUERY requests that the request target process the enclosed
content in a safe and idempotent manner and then respond with the
result of that processing. This is similar to POST requests but
can be automatically repeated or restarted without concern for
partial state changes.
Backwards compatibility, it’s never been valid to send a body with a GET, and software does enforce that (to varying levels)
It’s easier to create a new verb with the wanted semantics, than to change an existing one.