https://www.w3.org/TR/security-privacy-questionnaire/#questions
2.1 What information might this feature expose to Web sites or other parties, and for what purposes is that exposure necessary?
This feature does not expose any new information to Web sites or other parties.
2.2 Do features in your specification expose the minimum amount of information necessary to enable their intended uses?
Yes (none).
2.3 How do the features in your specification deal with personal information, personally-identifiable information (PII), or information derived from them?
No handling of personal information, PII, or information derived from them.
No handling of sensitive information.
2.5 Do the features in your specification introduce new state for an origin that persists across browsing sessions?
No.
2.6 Do the features in your specification expose information about the underlying platform to origins?
No.
No.
No.
No.
No.
2.11 Do features in this specification allow an origin some measure of control over a user agent’s native UI?
No.
None.
2.13 How does this specification distinguish between behavior in first-party and third-party contexts?
No distinction; no special considerations for use of the feature by third-party resources.
2.14 How do the features in this specification work in the context of a browser’s Private Browsing or Incognito mode?
No change to behavior in Private Browsing or Incognito modes. No features of the specification that would allow for correlation of a single user's activity across normal and private browsing / incognito modes.
2.15 Does this specification have both "Security Considerations" and "Privacy Considerations" sections?
Yes.
No.
Gap decorations are purely a painted effect and should be handled no differently from existing painted effects such as backgrounds and borders.
No special considerations for this feature.