What are swz files in Flash?

When I build my project I get a bunch开发者_如何学Python of swz files in the release/debug directory.

What are they?

They are quite big (1 mb in total) i just delete them, my swf works fine without them, so why are they there?

Adobe Flex Signed RSL file.

SWZ file is an Adobe Flex Signed RSL. Use Flex 3 runtime-shared-libraries (RSLs) to reduce the size of your flash applications and thereby reduce the time required to download the application. RSLs are just SWF files whose code is used as a shared library between different application SWF files. Signed RSLs (SWZ) are libraries that are signed by Adobe and may be stored in the Flash Player Cache, which can be accessed by applications from any domain.