Custom pop-up cover for always show position

Configuration Frontend
1

Hello,

I’m trying to add an item to the Cover pop-up (more-info-controls for cover)
I have already succeeded in modifying the “hui-generic-entity-row” element, but I can’t do it for the pop-up part :frowning:.
I would like to add to the right of the progress bar, the position of my roller shutter (to have it in constant display), exemple :
pop-up-with-position

I have see in the project “frontend-dev” the class MoreInfoCover (more-info-cover.js) or HaLabeledSlider (ha-paper-slider.js) but I do not know if it is possible to custom like this :

class CustomCoverCard extends HaLabeledSlider {
//my code
}

if you have any leads or example, I am interested.