Hello TAG!

I'm requesting a TAG review of:

• Name: The new "allow-top-navigation-by-user-activation" <iframe sandbox> flag
• Specification URL: https://html.spec.whatwg.org/multipage/browsers.html#attr-iframe-sandbox-allow-top-navigation-by-user-activation
• Explainer, Requirements Doc, or Example code: see https://github.com/WICG/interventions/issues/42 for some background, and note how the proposal morphed from initially changing the behavior of allow-top-navigation to introducing a new keyword, allow-top-navigation-by-user-activation
• Primary contacts: @domenic, @lubin2010

Further details (optional):

• Relevant time constraints or deadlines: Chrome is hoping to ship this in a branch that will branch March 2, so any feedback before then would be helpful.
• I have read and filled out the Self-Review Questionnare on Security and Privacy. Although this touches on related areas, it's largely a strengthening of the isolation that was present before (with allow-top-navigation), and none of the questions seem directly relevant.
• I have reviewed the TAG's API Design Principles

We'd prefer the TAG provide feedback as (please select one):

• open issues in our Github repo for each point of feedback
• open a single issue in our Github repo for the entire review (preferably comment on https://github.com/whatwg/html/pull/2292)
• leave review feedback as a comment in this issue and @-notify [github usernames]