A list is a list of related pages used for {{#pn:}}.
Usage
Each list page is a newline-separated list of page IDs. To specify a custom link text for a page, add | and then the link text after the page ID. To specify the link text for the page for the entire group, add a line that starts with | and then has the link text.
In a page, you can then add {{#pn:abc}} to use the list at Data:lists/abc.