If you are looking for the decompiler itself, visit https://github.com/jindrapetrik/jpexs-decompiler
List of issues
: The issue tracker is now writable again and logged users can download files too. But note that our support is very LIMITED.
#1366 Adding scripts to swf file
Labels: Adding script
A year ago I asked if this is possible and the answer I got was "not yet". Will this answer change in the near feature? Thank you, Wex
Adding new scripts or classes for both AS1/2 and AS3 added in nightly 1804. You can find it under context menu of scripts folder. I am closing this issue. Create a bugreport if you find any problem with script adding.