Comment by cryptonym

Recommended supported length is at least 8k.

Of course I don't advocate oversize URLs. That's a point of RFC10008.

Let's say we build a service for image transformation or image information extraction. Get isn't practical. QUERY with image as body could be a valid usage, regardless of caching. It conveys information that request is idempotent and can be retried with no impact on data, contrary to POST. If your http client is configured to support this, it can potentially improve reliability.