[flohofwoe]

Maybe the implementation is smaller than a typical FORTH?

For instance the FORTH implementation I'm somewhat familiar with (on the KC85 8-bit home computer) was an 8 KByte ROM module, which was packed to the brim - and it wasn't a luxurious FORTH by any means. This Mouse compiler seems to fit into 2 KBytes.

[_a_a_a_]

Can't remember but have read you can bootstrap a forth interpreter from an amazingly low number of bytes. Maybe more of theoretical interest than practical but still.