{{Extra collapsed text}} is designed to create collapsed sections in infoboxes, and with Category:music infobox templates in particular. You can use it with the |Misc= or |Tracks= parameters of the {{Infobox song}} template, for example.

{{Extra collapsed test |text=collapsed text |expand=yes }}

|text=
is a required parameter used to specify the content for the collapsed section.
|expand=yes
is an optional parameter used to change the default state from collapsed to expanded.