Install browser-plugin-gnash by entering the following commands in the terminal:
sudo apt update sudo apt install browser-plugin-gnash
GNU Shockwave Flash (SWF) player - Plugin for Mozilla and derivatives
GNU Gnash is a free GPL'd SWF player. It runs as a standalone application on either the desktop or embedded devices, or may be used as a plugin for several popular browsers. It supports playing media from a disk or streaming over a network connection. . GNU Gnash is based on GameSWF and supports most SWF v7 features and some SWF v8 and v9. SWF v10 is not supported by GNU Gnash. . Included in the Gnash is an XML based messaging system, as specified in the SWF specification. This lets a SWF animation communicate over a TCP/IP socket, and parse the incoming XML message. This lets an animation be a remote control for other devices or applications. . This package includes the plugin for Firefox/Mozilla Web Browser. The plugin works best with Firefox 1.0.4 or newer, and should work in any Mozilla based browser.