[EXIM] internal documentation about optionlist ?

Is there any documentation about the internal structure of drivers ?
Specifically, I'm trying to find ouit what the difference is between a
driver options that is 'opt_hidden' vs one that is 'opt_public' vs one
that is 'opt_hidden|opt_public'.

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j.

James FitzGibbon                                                james@???
System Engineer, ACC Global Net                   Voice/Fax (416)207-7171/7610

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