[ChrisSD]

Could you not use webNavigation[0] to check the url and permissions API to ask for permission[1] if necessary?

EDIT: Or tabs.onUpdated if webNavigation doesn't fire for hash changes[2]

[0] https://developer.mozilla.org/en-US/Add-ons/WebExtensions/AP...

[1] https://developer.mozilla.org/en-US/Add-ons/WebExtensions/AP...

[2] https://developer.mozilla.org/en-US/Add-ons/WebExtensions/AP...