Yes, you read it right Apache. The goal of project is to provide high quality stable Flex development environment to Emacs users.
This code in on early stage, don't expect too much out of box.
Put build.el file in root of your Flex project. It must contain build target, that similar to code below:
;; fcsh-mode compile settings ((compiler "mxmlc") (flags "-incremental=true -optimize=true -actionscript-file-encoding=UTF-8") (script "/absolute/pathTo/yourProject/Main.mxml"))
than do M-x flashdev-fcsh-build