In the Conformance section, it says that all notes are non-normative.

However, there are multiple notes that contain normative keywords.

• https://w3c.github.io/web-nfc/#issue-container-generatedID-2
• https://w3c.github.io/web-nfc/#issue-container-generatedID-4
• https://w3c.github.io/web-nfc/#issue-container-generatedID-20
• https://w3c.github.io/web-nfc/#issue-container-generatedID-26
• https://w3c.github.io/web-nfc/#issue-container-generatedID-31