SBS Definition?

[Bluegill Budd]

I have looked at the great flies posted labeled SBS. Does that stand for Smallmouth Bass Streamer?
While some might be streamers the B-2 Stealth Bomber is by the tier's description a "A Catskill stonefly/attractor".

So then, what does SBS mean in the titles of the flies?

[oldster]

Step by step

[Bluegill Budd]

Thanks - didn't think of that one.