This template stands for "Public watchlist redirect", and is intended to simplify the process of adding redirects in the main namespace to 'shared watchlist' pages, suitable for use with the {{public watchlist}} template. It is best used in conjunction with {{pwli}}, a similar template for articles in the main namespace.
The pwli template will add a bullet-pointed line to the watchlist page containing links to the article specified as its parameter and to its talk page. Using the pwlr template with the name of a redirect will add a similar line with two bullet points. Thus, typing the following: {{pwli|Foo}}{{pwlr|Fooism}} will produce the following:
(Be aware that subst'ing appears to add a newline before the text it substitutes, which will affect the spacing of your list as you add new items to it. As you can see, to make the redirect "Fooism" display as an indented sub-item of "Foo", the two templates had to be typed on the same line.) -- Antaeus Feldspar 20:44, 3 March 2006 (UTC)