Although the Flash authoring and Flash Player software have always been closed source, Macromedia, and later Adobe, have for a long time opened various formats

Although the Flash authoring and Flash Player software have always been closed source, Macromedia, and later Adobe, have for a long time opened various formats used in the Flash ecosystem. Some examples: https://www.adobe.com/content/dam/acom/en/devnet/pdf/swf-file-format-spec.pdf https://www.adobe.com/content/dam/acom/en/devnet/pdf/swf-fil... https://www.adobe.com/content/dam/acom/en/devnet/pdf/amf-file-format-spec.pdf https://www.adobe.com/content/dam/acom/en/devnet/pdf/amf-fil... https://en.wikipedia.org/wiki/Tamarin_(software) https://en.wikipedia.org/wiki/Tamarin_(software)