What is a "PI marker" or "programming instruction marker"

[Jeremy H. Griffith]

On Fri, 30 Nov 2012 13:21:18 -0800, Robert Lauriston 
<robert at lauriston.com> wrote:

>I don't see any mention of Oxygen in that thread.

Oxygen uses the DITA-OT for output, like most others,
so it was directly applicable to Oxygen whether the
editor used was Oxygen or not.

-- Jeremy H. Griffith, at Omni Systems Inc.
  <jeremy at omsys.com>    http://mif2go.com/