{{Pf}} is used to conveniently link to a ParserFunction, along the lines of {{tl}}. Pf stands for ParserFunction.
Usage
{{ParserFunction|parser function}}, this creates a direct link to the relevant function, omit # and colon, e.g. use {{ParserFunction|ifexpr}} to get {{#ifexpr}}.
{{ParserFunction|parser function|1st parameter|2nd parameter|3rd parameter|4th parameter}}, this creates a link with parameters include, e.g. use {{ParserFunction|ifexpr|1+1>1|true|false}} to get {{#ifexpr:1+1>1|true|false}}. For parameters with equals signs, use {{ParserFunction|1=parser function|2=1st parameter|3=2nd parameter|4=3rd parameter|5=4th parametr}}, e.g. use
{{ParserFunction|1=ifexpr|2=1+1=1|3=1+1=1|4=1+1!=1}} to get {{#ifexpr:1+1=1|1+1=1|1+1!=1}}.
Use |_code=yes to wrap the output in <code>...</code> tags, e.g. {{ParserFunction|ifexpr|1+1>1|true|false|_code=yes}}produces {{#ifexpr:1+1>1|true|false}}.
Template documentation