Assassin's Creed Origins was leaked by a t-shirt, Assassin's Creed Odyssey was leaked with a keyring, so it makes sense that the Nintendo Mini Switch 2 should be leaked by a silicone sleeve accessory. The potential reveal comes from a Tweet which you can see below, which includes an image of a black-and-white silicone sleeve for the console. There's a bigger, wider screen, and apart from that the Nintendo Mini Switch 2 looks… pretty similar to the Nintendo Switch.
In the bottom left-hand corner of the below image you can faintly see the words "Nintendo Mini Switch 2", which seems like a bit of a mouthful but as that's what's on the packaging… *shrugs*.
Earlier reports claimed that it would be smaller and cheaper than the first Nintendo Switch, (hence the 'mini' in the name), but until Nintendo officially reveals the console we'll have to make do with this sleeve. Nintendo has a tendency to do Directs whenever the hell it wants, so there's no saying when we might get a glimpse of the console for real. Just keep your fingers crossed for either some more leaks so we can get a better idea of the appeal of the Nintendo Switch Mini, or for Nintendo to pull back the curtain on the console itself.