They don't tell you what the actual switches are on the page, but they look like Cherry's low-profile switches, which will hopefully mean that the keycaps can be customized.
Taller keycaps like SA or MT3 profile might not be great with such short travel, but GMK/OEM/Cherry profile would probably be comfortable.
Could also be choc v2s, which I say is more likely, because otherwise they'd plaster cherry logos somewhere on the page.
There's a bunch of compatibility problems with those. Cherry, GMK, and PBT MT3 all don't work according to a geekhack thread I see. Cherry's lp switch would probably have similar issues.
They're a bit on the obscure side, even among low profile keeb people. Very few boards support them (I think there's like a corne variant and maybe one or two other one offs), and they only come in 3 types.
I remember the 'US electrical socket with no ground pin' shaped stem form the V1s, and thought it was a shame that it was so hard to source keycaps for them. I never tried more than some loose switches I got on sale, since, you know. No broad support/interest, it seemed.
Luckily that's increased. MBK keycaps came out and which were some of the first to not have flat tops. Then they put out a colored variant, and there's been a few other companies readying new ones (MCC, WRK(work louder), and chicago steno if you want something really fancy). Nothing like mx mount switches though, with a few dozen group buys running at once but it's getting easier to find good stuff.
Taller keycaps like SA or MT3 profile might not be great with such short travel, but GMK/OEM/Cherry profile would probably be comfortable.