The Steam Deck website has an Easter egg that proves Valve isn't afraid of making a few jokes at its own expense, even when it comes to leaks.
If you head to the official site's software page, then scroll down to the section with the heading "A new Steam operating system," you'll see it ends with a linked passage saying "Hold on to your butts!" Click the text, which is a reference to Samuel L. Jackson's famous line in Jurassic Park, and a new subsection will roll out with another Jurassic Park reference to go more in-depth on how Steam Deck uses a Linux operating system. OK, so it was a UNIX system in the movie, but close enough.
The fold-out Linux section is illustrated with an image of two people looking at an old CRT computer monitor with a very familiar, very Hollywood-looking computer interface. It's another Jurassic Park reference, but we need to go deeper. On the side of the screen is a picture of the G-Man from Half-Life looking smug and smoking a pipe, and there are some sticky notes above and below his picture.
The top sticky note demonstrates where the Steam Deck logo - a semicircle surrounding a smaller circle - comes from: it's just the Steam logo with the left bit chopped off. I feel silly for not realizing that already, but moving on. The second note has the words "Steam Pal" crossed out and "Steam Deck" circled, and the third has "Todo: Delete 6.js" written on it. Those are both references as well, but not to Jurassic Park: the first solid indications of Steam working on a handheld device arrived via datamine back in May, when data trawlers noticed references to something called "SteamPal" in a Steam UI file named 6.js.
Major props to Valve for staging a whole photo shoot just to make fun of itself for leaving some data out where it shouldn't have. You still have time to get your Steam Deck pre-order in, though the servers have been struggling ever since they opened earlier today.
GR's Heather Wald points out that Steam Deck might look like a Switch, but it's a true miniature PC with all the room for customization that entails.