The display or the typing? The display is just a bunch of blunt tip pins that raise or lower depending on what needs to be displayed
Typing depends on the device, some are as simple as a qwerty board with Braille on the key caps, some are based on gesture, some are based around finger pads and learning the various combinations of strokes to make letters
Edit: rereading your question I think you’re asking about the file format? Sorry I don’t know much about that!
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