ਫਰਮਾ:High-risk

This template determines whether its first parameter can be parsed by parser function #titleparts.

{{parsable|<parameter>}}

asks #titleparts to extract the second part of <parameter>. It returns true (i.e., non-blank) iff this request produces something different from <parameter>. If <parameter> is blank, the result of the test is false (because {{#titleparts:<parameter>|1|2}} then returns a blank string, which is not different from <parameter>).