Implement the display-capture feature policy from the Screen Capture spec. https://w3c.github.io/permissions/#dom-permissionname-display-capture This policy allows restricting access to the getDisplayMedia() API in embedded resources.
This feature-policy enhances privacy/security by giving an embedding frame control over an embedded frame's access to the getDisplayMedia API. Without it, some attack vectors would be open to the embedding frame, as it would be able to visually inspect most things which the embedding frame draws to the screen.
Explainers: https://docs.google.com/document/d/1qb26hiLwPO8XnvHvBjgsGDGXNI5ABvGA32461uERRSA/edit?usp=sharing