Add an additional section with a task for interested contributors;
"Work through the PR database".

Prompted by Doug <Doug@gorean.org>, who in an e-mail to an interested
contributor in -hackers wrote;

On Sun, Jul 18, 1999 at 12:01:43PM -0700, Doug wrote:
[...]

Step three, (and I can't believe this isn't mentioned in the handbook) if
there isn't anything on that page that looks interesting to you, take a
look at http://www.freebsd.org/cgi/query-pr-summary.cgi and see if
anything there strikes your fancy. Look first at unsassigned PR's, but
if one of them that is assigned to someone looks like something you can
handle and have time to work on, mail the person it's assigned to and
ask them about it.

[...]

So now it is mentioned in the Handbook :-)