Codex

$EnablePageListProtect
When set to 1 (which is the default), causes (:pagelist:) and (:searchresults:) to exclude listing any pages for which the browser does not currently have read authorization. Setting this to zero means that read-protected pages can appear in a listing, but can also speed up searches considerably (because page permissions do not need to be checked).
$SearchPatterns
An array of page name patterns to be required or excluded from search and pagelist results. In order to be included in a search listing or page listing, a page's name must not match any pattern that is delimited by exclamation points (!) and must match all other patterns. See Cookbook:SearchPatterns.
$SearchBoxOpt
For example $SearchBoxOpt ['target'] = '$DefaultGroup.Search';
$EnablePageIndex
When set to 1, causes PmWiki to maintain a "link and word index" in $PageIndexFile which significantly speeds up categories, backlinks, and searches.
$PageIndexFile
The location of the "page index" file for (:pagelist:), defaults to $WorkDir/.pageindex.
$PageListCacheDir
The name of a writable directory where PmWiki can cache results of (:pagelist:) directives to speed up subsequent displays of the same list. Default is empty, which disables the pagelist cache.
$PageSearchForm
The page to be used to format search results for ?action=search (unless the current page has a "searchresults" directive in it). This variable can be an array, in which case the first page found from the array is used.
$FPLTemplatePageFmt
The pages to be searched for a pagelist template specified by a fmt=#xyz parameter. Defaults to searching the current page, Site.LocalTemplates and Site.PageListTemplates.
It can be customized to look in other pages.
Or declare defaults for the template array:
$EnableUndefinedTemplateVars
This variable controls how undefined {$$Variable} is processed in includes and PageList templates. If set to 0 (default), undefined {$$Variable}s are removed from the included section or template. If set to 1, undefined {$$Variable}s are displayed as is, with {$$...}. Note that PmWiki versions 2.2.13 and earlier kept unset include/template variables.
$EnableUndefinedTemplateVars = 0; # Delete unset raw template variables
$EnableUndefinedTemplateVars = 1; # Keep and print unset raw template variables


This page may have a more recent version on pmwiki.org: PmWiki:PagelistVariables, and a talk page: PmWiki:PagelistVariables-Talk.