This template exists to provide a way to easily escape a raw double pipe character (
||) in a situation where markup containing it (e.g. a table) needs to be passed as a parameter to a template. Parser functions will treat all the raw pipe characters as parameter dividers. This template 'hides' the pipes from the MediaWiki parser, ensuring that it is not considered until after all the templates and variables on a page have been expanded. It will then be interpreted as a table row or column separator.