The Apache Flex project provides a number of binaries as a convenience for those who do not wish to compile the source themselves. These binaries are not official Apache Flex releases. It is recommended that you download the officially released source distributions and verify the signatures of the downloaded files before opening them.
The Apache Flex SDK Installer is a utility for downloading and installing the artifacts and dependencies needed to use the Apache Flex SDK with a third party IDE. The official release of the Apache Flex SDK Installer is the source which can be found here or here (SVN). The Apache Flex SDK Installer is also made available as a convenience binary here and through the Apache Flex SDK Installer Badge. The Apache Flex SDK Installer downloads the binaries, not the released source of the Apache Flex SDK.
Note: the installer downloads other files besides the Apache Flex SDK. For more information, please read the Apache Flex SDK Installer page.