Prompt after install
For more information on how to implement a post-install page or dialog, see Best practices for onboarding, upboarding, and offboarding users.
As mentioned in the Add-on policies, if your extension collects user data in association with features that run in the background, such as ad blocking, you need to make sure the data collection is not activated until you have obtained user consent.
We have talked about how you could let users opt-out of collecting technical and interaction data but must have users opt-in to collecting personally identifying information. Before you design your extension features around your consent requests, it is important to understand how these options affect your design.
Where you provide the user with an opt-in option, the related feature must be turned off by default and only turned on once the user has actively agreed to use that feature.
Where you provide the user with an opt-out, option the related features can be turned on by default but must be turned off if the user indicates they want to opt-out.