Unknown template parameters category?

My good denizens of London,
I have just fixed two pages where the template parameter "Locked with" of Template:Action was preposterously spelled as "Locked With" (with a capital W).

This caused that parameter to be ignored altogether, and in turn some confusion to Yours Truly. I have heard rumours of a method to identify failed parameter substitutions and wonder if it would be feasible to implement that method on this wiki? For now, I have created the appropriate talk page.

Edit: Speaking of misspellings, I had confused "Locked" with "Unlocked". Fixed now.