An Adobe SWC file is a package of precompiled Flash symbols and ActionScriptcode that allows a Flash or Flexdeveloper to distribute classes and assets, or to avoid recompiling symbols and code that will not change. SWC files can be generated by the Flash authoring tool, and by Flex. They are sometimes referred to as class libraries and cannot be directly executed by the Flash Player.
A SWC file is compressed by means of the ZIP archive format. Renaming the extension of a SWC file to "zip" will allow any ZIP-compatible decompression software to show the contents of the file.
An uncompressed SWC file contains at least a catalog.xml file, and a SWF file, usually named "library.swf". It may also contain other files, such as CSS files. The catalog contains a list of the ActionScript classes contained in the library, their dependencies, and modification dates.