Its in the CoronaLabs github : https://github.com/coronalabs/framework-storyboard-legacy. So you can include it in your project.
Great! Thanks!
Meanwhile, I discovered the bugs that caused me to switch were related to missing files used in Widgets, not to Storyboard at all. Turns out, Widgets do not tell you what the problem is when a file is missing — you just get mysterious errors with no references to functions or cause.
We made storyboard.lua available on Github as @nmichaud said. Simply drop it into the folder with your main.lua and even if we get rid of it, you would still have it. That said, we will not be updating storyboard.lua any more. If do something like we did with Graphics 2.0 where it had breaking changes and those changes break storyboard.lua, you’re on your own to update it. Composer is the supportable path going forward.
Rob