>My first  question is, can I  define a FAC  in one location and  have it
>accepted as valid from within different, nested filelists?
 
No, each FILELIST must have a  comprehensive list of all the FAC's you're
using, otherwise there could be  conflicts among filelists (maintained by
different people).
 
>My  second question  is  in regard  to  hiding  some, or  all  of a  FAC
>definition. I was under the  impression that by inserting "HIDE=" within
>a FAC  definition, the remainder of  that line would not  be written out
>when a copy  of the filelist is sent  out in response to a  GET or INDEX
>request. I  defined a FAC  within the header of  one my lists  using two
>lines:
>
>*+ UMO= * List owners at this site
>*+ UMO= HIDE=OWNER(TEST-L),OWNER(MAILBK-L)
 
It's HIDE=YES,
 
>I am not sure  what I missed, but I get the impression  that I should be
>defining my FAC's somewhere other than the filelist headers.
 
No, you were doing the right thing.
 
>My last question  is in regard to one of  the hardcoded FAC definitions.
>What exactly is "HDR= See list header" used for, and how is it defined?
 
It means the definition is too long and/or too complex to be shown in the
filelist header,  and comes from the  definition of the list  by the same
name.  That's  what  happens  to  the  archives  of  the  list  when  the
access-rights  part  of  "Notebook=" keyword  doesn't  specify  something
simple      like     "Public"      or      "Private",     but      rather
"Owners(ABC-L),Postmasters,Owners(XYZ-L)".
 
  Eric