Syntax: one or more CSS selectors
These CSS selectors define portions of HTML documents to keep (e.g. main articles, sections etc.). All text outside matching elements will be removed from the searchable text. A matched element includes the open tag through the matching balanced close tag (if not a void element). Only valid HTML 5 elements may be matched. Links will be unaffected. A matching tag with no close tag given in the document will generally match through the closing implied by HTML (e.g. end of parent element). Documents that match no Keep Selectors will be unaffected.
A limited subset of CSS selector syntax is supported; see Ignore Selectors (here) for details. Setting added in version 25.0.0.