Initially I also though that they are just using same trick as what they have for rest of the custom colored indicator shapes. But after looking at some teardown videos of EP-133 it seems to be using real 3x(10+1)segment display module for the number section.
So this might still be specially shape mask on top that 10 segment display. But considering that it by itself isn't exactly common (compared to 7 or even 14 and 16 segment displays) I wouldn't be too surprised if they were able to find a factory in china that would make a customized segment led modules in batches of few thousands. At the end of day what are 7 segment displays if not a bunch of LEDs and light guides molded into single plastic case. It wouldn't be cheap but for a premium product with focus on visual design and experience like what the teenage engineer makes it doesn't seem impossible.
As for something more accessible to a hobbyists - people have been experimenting with placing custom cutouts on top of LED displays with quite good looking results.
It can be as simple as thin laser cut stencil on top of LED matrix display https://www.youtube.com/watch?v=oLgUtjyKO6Q
With thicker 3d printed mask you can even shift the positions of segments https://www.youtube.com/watch?v=gt2merZcuno
So this might still be specially shape mask on top that 10 segment display. But considering that it by itself isn't exactly common (compared to 7 or even 14 and 16 segment displays) I wouldn't be too surprised if they were able to find a factory in china that would make a customized segment led modules in batches of few thousands. At the end of day what are 7 segment displays if not a bunch of LEDs and light guides molded into single plastic case. It wouldn't be cheap but for a premium product with focus on visual design and experience like what the teenage engineer makes it doesn't seem impossible.
As for something more accessible to a hobbyists - people have been experimenting with placing custom cutouts on top of LED displays with quite good looking results. It can be as simple as thin laser cut stencil on top of LED matrix display https://www.youtube.com/watch?v=oLgUtjyKO6Q With thicker 3d printed mask you can even shift the positions of segments https://www.youtube.com/watch?v=gt2merZcuno