Who else has noticed the Kingdom Hearts wallpaper on the computer screen in Broken Sword 3?

You mean on the computer screen inside the tech room, used by the lady that validates the security card, while playing as Nico disguised as Petra, within the Susarro castle in Prague?

Yeah I've seen it.

...and looks just like this:(view attachment)

yay! =)

Actually I only recently saw it for myself, I reinstalled my copy of BS3 along with the rest of the series to celebrate the release of BS5, and while in the computer room I noticed one of the monitors has the default autumn wallpaper for windows, so while checking the rest of the monitors i noticed that the one used by the Tech Lady had a vaguely familiar wallpaper, sure enough there can be no doubt that it's one and the same wallpaper.

I guess since i used to have a crappy pc back when i first played the game i never noticed, now it's easy to see with 16x10 resolution.