customview.cgi is no longer on www. and will redirect to $JOURNAL/data/customview?..... An s1style will only show for a user if: it's owned by the user, it's owned by system, or they explicitly trust it. daveman692 added a console command to set a list of trusted s1styles. Its keyname is "trusted_s1" and value is comma-separated list of s1styleids.
So the s1styles command and the customview.cgi url change need to be documented. Since I'm only semi-knowledgeable about styles FAQs, someone else needs to determine where they should go. :)