Problem
The PST features in wikitext are things like ~~~~ (becomes a signature on-save), and {{subst:#time:}} which can insert the current date.
These can be used in templates and in passing text, but not inside extension tags such as <ref> or <gallery>.
Use cases
- Adding a signed caption inside a gallery, for example on a wikiproject page, or talk page. <gallery>File:Example|I like this one. ~~~~</gallery>.
- Using the current date as the default for template parameters. <ref>{{Cite web|title=|url=|access-date={{subst:#time:Y-m-d}}}}</ref>