This template is only to be substituted, and displays a warning if not substituted correctly.

Usage:

The template is used to identify the timestamp of an edit on a talk page if the author failed to place a timestamp (this is a result of using 3 ~ as ~~~). There is one parameter, which is the timestamp of the editor (omit the "UTC"). This can be found in the page history. The template must be substituted or it will display a warning. This is so that the identification of the editor is permanently placed on the page and is not affected by changes to this template.

Correct substitution:

{{subst:undated|12:04, 1 April 2001}}

...displays as:

—The preceding undated comment was added on 12:04, 1 April 2001 (UTC)

...while incorrect transclusion:

{{unsigned|12:04, 1 April 2001}}

...displays as:

This template must be substituted.