Is it possible for an Overlay Extension to default / automatically open and/or close?

[BarryCarlyon]

Yes you’d enable it in the overlay slot instead of a component slot.

Overlays start open.
Component’s need to be opened by the user.

@ccom

In other words, instead of an overlay extension appearing as a thumbnail as option to open, is it possible that either

An overlay extension in the overlay slot starts open

@ccom

Along the same lines, is it possible for an Overlay Extension to self-minimize?

Extensions Reference

window.Twitch.ext.actions.minimize()

This function causes your video-component or video-overlay extension to be minimized.

You call that and it will minimize video overlay or video componenet

@ccom

a) The extension can self open by means of running an API call?

No thats not possible, but if you are active in the “overlay” slot you can make all your stuff be “display: none;” and respond to your custom API to become “display: block”