Template:PrefixIndex/doc

Usage
This template transcludes Special:PrefixIndex (yes, you can do that!) along with some extra stuff, to produce a list of pages with names beginning with a certain prefix. Enter the prefix in the first unnamed parameter. To split the list into multiple columns, enter the column width (e.g. 15em, or 30em) in the  parameter. To hide redirects from the list, enter anything in the  parameter and to strip the given prefix from all the page names, enter anything   parameter.

You can do most of this stuff (except for the columns and colwidth part) by directly transcluding the special page. Its documentation and talk can be seen at the (bizarrely located due to technical reasons) pages Wikipedia:Special:PrefixIndex and Wikipedia talk:Special:PrefixIndex.

Like, for example:

The main thing this template adds is the ability to specify columns and column width.

Compare this to the equivalent usage with PrefixIndex:

Like, for example:

Syntax
Vertical format that takes up a lot of space and is easy to read: Horizontal format:

Parameters

 * or – (REQUIRED) &mdash; prefix to list/search from &minus; defaults to the current page that the template is transcluded from
 * – (OPTIONAL) &mdash; width of columns to use, in em units, e.g. "30em".
 * or – (OPTIONAL) &mdash; if set, does not display redirects
 * – (OPTIONAL) &mdash; if set, strip the prefix value from displayed list items