In the mobile app, when I long-press the reactions area, I can see the list of all reactions and all people who have reacted with those reactions. I can also tap on the reactors which gives me the option to mention them, or send them a DM.

Such a thing is not available in webapp/desktop, there is only a tooltip on hover, which does not really work as an actual list of reactions.

I propose to improve this so that this feature - a true list of reactions which can be interacted with - is present in webapp/desktop as well.