Open-Flash author here. Open-Flash was originally intended to be a fork of Shumway, but it ultimately became a fully separate project intended to provided modular libraries to handle SWF files. I had less time to push the project forward in the last few months.

It currently provides one of the strongest models for parsed SWF files and AVM1 bytecode, and the corresponding parsers and emitters. These libraries are in use to process SWF files automatically (remap identifiers, edit tags, compress files). The end goal was to provide a player, but Ruffle already has relatively good support, so the goal is shifting to automatically convert SWF files to other languages and help with migrations. The current focus is on AVM1 (Actionscript 2) decompilation.