It looks like you're trying to share or post about the file — likely referring to a version of the adult Flash game Super Deepthroat .
These numbers typically refer to the version history. In the world of indie Flash dev, "1.21" would be the engine version, while "1b" often signified a specific "beta" or "build" that included certain bug fixes or added assets. Super Deepthroat SDT1 21 1b.swf
However, the "Flash Era" effectively ended in December 2020, when Adobe officially stopped supporting the Flash Player due to security vulnerabilities and the rise of more efficient technologies like HTML5. This move rendered thousands of games—including various versions of SDT—unplayable on standard modern browsers. The Preservation Movement "Super Deepthroat SDT1 21 1b