Many instances will absolutely want to do their own branding across the board, and that’s totally fine, but I also believe that many would like to see a unified approach to the platform. The beauty of the decentralization is that site admins are free to run their instance however they like.

No such feature exists yet on the desktop version, but I am sure it’s on the wishlist already. Apps might be able to implement this themselves, but I can’t say whether any have yet.

Edit: clarified