Where did you look? Googling STEP turns up a bunch of stuff and searching on ISO
10303 (the ISO document number) gets you to a bunch of technical committees that
actually handle the work of building the standard.
The founder of STEPtools, Martin Hardwick, has been on STEP technical committees
for many years and has helped write the standard. He's currently team leader of
the STEP manufacturing group. I'm sure you'll find the answer here or through
or through the forums they sponsor.
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