Bjork.NET now offers a range of free, open source FB3 and FB3-style core files.

• The flagship of this range is the "TURBO", which is a 100% FB3-compliant drop-in replacement for the official Fusebox.org core file. The Turbo core is optimised for performance, and will give increasing gains as the size and complexity of your application grows.

• The "LITE" core offers a pure subset of the FB3 standard API, and provides even greater performance gains than the Turbo. Because it only supports a sub-set of the FB3 API, the Lite core will only be useful for those developers who are happy to work without some of FB3's substantial API set. On the other, you can be confident that any application you develop around the Lite core will run perfectly well with the official core file.

• The "EASY" core introduces a controversial and risky variation on the FB3 standard. Some developers, including Lee Borkman, have suggested that the current details of the FB3 nested layouts system result in a slightly asymmetrical and unintuitive architecture. The Easy core removes the asymmetry, with the intention of creating an architecture that is easier to comprehend and communicate. As an added bonus, the Easy core offers a slight performance gain over the FB3-compliant Turbo core. NOTE: Any application built around this core file wil not be FB3-compliant, and will not function with the offical core file.

• "LITE-N-EASY", as the name implies, simply offers a combination of the Lite core's FB3-subset API and the Easy core's simplified nested layouts system. NOTE: Any application built around this core file wil not be FB3-compliant, and will not function with the offical core file.

• Finally, the "RunAction" add-on provides a method of efficiently calling an entire fuseaction from anywhere within your code. The called fuseaction is executed immediately, and then control returns to the originating code. The RunAction add-on is designed to work with any of the Bjork.NET core files, but it should also work perfectly well with the official Fusebox.org core and with a number of prioprietary cores. Note, however, that no other organisation has been involved in the development of the RunAction, and certainly no other organisation offers support should you encounter any problems as a result of using RunAction.