It seems that a lot of people are still unsure what the libs folder is actually for within a Flex Builder 3 project. Well if you’re not sure, here is its use – It for importing SWC files in to.
I know a lot of developers still use the library path to import SWC’s so that they are available for authoring and compile time. However you don’t need to do this anymore. just import your SWC (Cairngorm.swc for example) in to your libs folder within your project and Bob’s your Uncle (He’s my brother but there ya go :p), it’s available straight away.
No more addtional steps to add a SWC anymore. Yay!