Concerning recent developments of third party addons, and SE's DADT stance

[TitanMen]

Can you please name the add-on so everyone knows what you're talking about

[Iscah]

Can you please name the add-on so everyone knows what you're talking about

I'm pretty sure there are rules against naming add-on programs, whether consistently applied or not.

[Risvertasashi]

Can you please name the add-on so everyone knows what you're talking about

I can describe what it does.

It shows hidden telegraphs. There's a fair chance SE can't do anything about it, as the client probably needs to have oncoming AOEs in the client to prevent the latency issues notorious in the game's early life. This means, for example, in ultimate content (which was demo'd), and probably savage and ex as well, you can see where attacks are going to hit well in advance of when the client intended to show them to you.

There's gifs that have been passed around on twitter and discord and there's one on reddit right now too.

[BristolRuss]

Can you please name the add-on so everyone knows what you're talking about

You are innately familiar with the program in question, seeing as there are videos of your main account using said program on Twitch.