This is the {{Lake index}} or lake index article template.
It can be used to mark a page as a set index article about lakes. A lake index article lists multiple lakes, preferably with a description of their location and coordinates.
This template is usually placed at the bottom of the page and adds the page to Category:Set index articles on lakes.
This template can be used without any parameters like this:
{{Lake index}}
Editors may want to control how the page is sorted in Category:Set index articles on lakes.
This is accomplished by adding the sort key as the "name=" parameter.
For example, List of lakes named Diamond is sorted using:
{{Lake index|name=Diamond}}
or, in short:
{{Lake index|Diamond}}