It looks like it was first used and introduced in 5130d80d79 (diff-8a4a36a7728107b2ccaff2cb405dbab229a1100fe50653a63d1aa9ac10ae45e8R305) but the But the usage was removed in 4c6a31cd6e (diff-8a4a36a7728107b2ccaff2cb405dbab229a1100fe50653a63d1aa9ac10ae45e8)
5130d80d79 (diff-8a4a36a7728107b2ccaff2cb405dbab229a1100fe50653a63d1aa9ac10ae45e8R305)
4c6a31cd6e (diff-8a4a36a7728107b2ccaff2cb405dbab229a1100fe50653a63d1aa9ac10ae45e8)