This is an auxiliary template allowing to encode "
|" within template and parser function parameters. To get the symbol in final output this template is unnecessary, better use "
|" which is rendered the same. Use this template in parameter values of templates and parser functions of which the result is used in table syntax, since this requires the "real" pipe character.
The same applies when a parameter is used literally for an internal link and you want to set a label.
This template cannot be used for putting the character as text in a wiki table; in that case, again, "
|" can be used.
Note that the table syntax code "
!" (exclamation mark) can be used directly in parameter values, as it's only special at the beginning of a line, so for that a template like this is not needed.