Questions from https://www.w3.org/TR/security-privacy-questionnaire/
2.1. What information might this feature expose to Web sites or other parties, and for what purposes is that exposure necessary?
This feature exposes unsanitized HTML to the clipboard using the async clipboard API. This information is already exposed by the existing DataTransfer API, so it's not something new that we're exposing with this feature. Sites have to opt into reading the unsanitized HTML content, else, they will get sanitized HTML by-default. To read unsanitized HTML via the async clipboard API, all the restrictions related to secure context, permission etc apply.
2.2. Do features in your specification expose the minimum amount of information necessary to enable their intended uses?
Yes.
2.3. How do the features in your specification deal with personal information, personally-identifiable information (PII), or information derived from them?
This API doesn't expose any new information that can't already be accessed via existing DataTransfer clipboard APIs.
This feature doesn't deal with any 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?
It doesn't distinguish between behavior in first-party and third-party contexts as the async clipboard APIs already have restrictions via Permissions.
2.14. How do the features in this specification work in the context of a browser’s Private Browsing or Incognito mode?
It works the same way in incognito mode.
2.15. Does this specification have both "Security Considerations" and "Privacy Considerations" sections?
No.
No interaction with documents regardless of its state. Web authors have to provide the HTML content via the async clipboard APIs.
N/A
No threat.
The API is only available from a secure context.
It doesn't leak data across origins.
No interaction with third-party pages.
We don't think there is any risk of legitimate misuse of this API. Browser parses the HTML string provided by the web author and creates a well-formed HTML document before it writes to the system clipboard. The target apps that reads this data will not be at risk of parsing malformed HTML.