What kind of drawing units are used in the API?

After some trial & error, I wrote the Macro below. It draws 6 horizontal lines, from the bottom to the top. After running it, we can infer that the origin is at the lower left corner. Fair enough.

My doubt is about such small values. What is the unit? The kilometer, perhaps?  :-)

BTW: I am using an ANSI (ansi.drwdot) page.

TIA

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SolidworksApi macros