In particular, you see it as a variation in the BSL forms. Songshan Shaolin tends to end with Hero in a horse stance but a few of the BSL forms end in this one-legged variation. BSL 8 comes immediately to mind as an example.

Note that we published a variation of Hero in a Horse Stance in our Jan/Feb 2001 issue in a photo-essay piece Busted! Kungfu Masters Reveal Their Favorite Military Police Attacks By John Brown and Martha Burr. Interestingly enough, it's an O-Mei version from my master, Tony Chen, and in the O-mei system, it's called Wu Song strikes the Tiger. Tony's interpretation of it is wild - he pulls a strike to the top of the foot, then to the groin, then a takedown and trap out of it. He also re-interprets it for knife fighting and bayonet fighting.