I used to enter about:reader URLs all the time for pages that Firefox Android wouldn't show the button for. Do you know where the moz-extension:// incantation f

I used to enter about:reader URLs all the time for pages that Firefox Android wouldn't show the button for. Do you know where the moz-extension:// incantation for this is? I would think it's a constant UUID, so maybe I just need to page through the source. There really should be an option for "always let me try Reader Mode."