An onion reference should be recorded with the same care as any other address claim, without treating mention, repetition or a screenshot as proof.
Capture the reference context
Record the publisher, visible date and surrounding explanation that introduced the onion claim.
A bare string without source context is difficult to evaluate later.
Preserve exact spelling
Character-level differences can create a different address, so retain the claimed form in a controlled evidence record.
Avoid presenting a reference as a clickable destination while its provenance remains unresolved.
Explain the limitation
State which parts of the claim were observed and which parts remain unsupported.
Transparent limitations are more useful than a confident statement without a review trail.