Run the best available document viewer installed on the system.  Intended for
use mainly as a proxy application in browsers, email clients, etc. that work
with PDF attachments.  By configuring the applications to use docviewer instead
of a specific document viewer, you can avoid having to reconfigure multiple
applications when switching viewers.  Your viewer selection is configured in
one place.

WWW: https://github.com/outpaddling/docviewer