Longer term solution should be similar to silica TextField / TextArea meaning that content should be zoomed / magnified when selecting text.

Maybe these events could be used for that... 

https://developer.mozilla.org/en-US/docs/Web/Reference/Events
```
MozMagnifyGestureStart 	  	Addons specific 	Two touch points start to move away from each other.
MozMagnifyGestureUpdate 	  	Addons specific 	Two touch points move away from each other (after a MozMagnifyGestureStart).
MozMagnifyGesture 	  	Addons specific 	Two touch points moved away from each other (after a sequence of MozMagnifyGestureUpdate).
```