Revoke access?
As in logging out? 
With Athom OAuth2, the online login screen where you have to consent to access, it is not possible for users to select exactly what they want to consent to. It’s all or nothing sadly 
Even though the dashboard does supports limited access and readonly scopes. Athom just has to improve their login consent page.
To clarify; when you login you are returned to the homeyboard.github.io site with an extra access token in the URL. This is just stored in your browsers local memory, and never shared anywhere. Revoking access is basically the same as logging out, or just exiting the page. Without the page open, nothing happens anyway. If you open the developer-tools in your browser by pressing F12, you can find it here:
When the installable Homey Pro app is approved by Athom, you can (on the HP23) create an API-key with exactly the access scopes you want it to have. And you can through the Homey app also revoke any API-keys you create.
But basically; there is no sign-out button anywhere at the moment 
Just close the page if you don’t want to use it anymore.
