The "sitemap-extra" setting:
This setting should be a TCL list divided into triples. Each triple defines a new entry:
The first term is the display name of the /sitemap entry
The second term is a hyperlink to take when a user clicks on the entry. Hyperlinks that start with "/" are relative to the repository root.
The third term is an argument to the TH1 "capexpr" command. If capexpr evaluates to true, then the entry is shown. If not, the entry is omitted. "*" is always true.
The default value is blank, meaning no added entries.