Adding a button to the settings page of an extension

[SenshiSentou]

Is there a way to add a button to an extension's settings page directly from the on_ui_settings callback? I've seen another extension inject it through javascript; is that the preferred (only?) approach? Thanks!

EDIT: I can add a button using shared.OptionInfo("Foo", gr.Button), but the onchange event isn't called on click. I then tried assigning these manually though btn.component.click(my_callback), but it errors out with type object 'Button' has no attribute 'click'. Same with js for calling a front-end method. Seems I can't access the component instance directly?

Also no dice using the component_args: Button.update() got an unexpected keyword argument 'click'