This is Minecraft Windows 11 Edition. This changes Minecraft to look much more similar to Microsoft's Windows 11. There are not many practical changes, just UI changes and more splashes. The new splashes are:

Owned by Microsoft!
Possibly Windows 13 Compatible!
Windows 12 Compatible!
:( A fatal error has occurred and your PC needs to restart. *Insert BSOD*
Sun Valley 3!
toot toot
Pizza Time!
Helikopter helikopter!
Sandstorm!
Do the Macarena!
Let me guess, you are playing sometime during now?
Do the Spider Dance!
Do not enter the Hall of the Mountain King!
Now Playing: Minecraft Music
For Windows 11 23H1+!
OpenGL 5.7!
Anyone can Play!
Raiding Area 51!
Because yes!
Absolutely not!
Mwahahahahaha!
Waluigi Invites Himslef!
Rest in power, Technoblade. o7
*Demonic Screeching intensifies*

The changes to the UI also affect the loading screen if using OptiFine. The loading screen works better when using monochrome logo, as seen in the images.