Solaris 10, SPARC.
While trying clean up my "/opt" directory, I saw the "sun_docs" directory.
I scanned the contents with "du -a", and also found a single, possibly related file (/var/opt/sun_docs/sundocs.html).
If I understand correctly, it looks like a local set of HTML files, designed to be ready by a locally running browser? It looks like it could be shared via http, if an admin knew how to turn that on.
I did google and check docs.sun.com.
-ben
That is not a directory that comes with the standard install of Solaris 10. It gets created if you install packages from the Solaris Documentation media. It is in no way system critical.
http://docs.oracle.com/cd/E19253-01/817-0550/6mgbg7ec5/index.html
The files can be viewed through a local browser or could be moved into a location within a webserver's DocumentRoot to make them viewable over HTTP.