Is there a way to change the icon of the client, not from the launcher but really from the game client?
Can you send a screenshot of what you want it to be.
When you start Minecraft, the launcher where you log in / and or directly start the game with a version opens first, and then the actual game opens.
With the launcher it is very easy to change the name and the icon, since it is a link, in direct applications with the game client, I have now imagined that there's a png or something in the Minecraft files that has the icon gives and which one can easily replace, only I would not know where and if something exists at all.
So I personally don't know how to do that. Look at Chip.de or something