SlackBuildsOrg/multimedia/freshplayerplugin

The main goal of this project is to get PPAPI (Pepper) Flash player
working in Firefox. This is done by impementing a wrapper, some kind
of adapter which will look like browser to PPAPI plugin and look like
NPAPI plugin for browser.

When loaded by browser it will search for libpepflashplayer.so in a
directory where it can be: if you have google-chrome from /extra or
chromium-pepperflash-plugin from Alien Bob installed it can use also
those versions. If for any reason it doesn't find your installed
version of the plugin, specify the full path in
~/.config/freshwrapper.conf.
You may find a sample configuration file in the docs folder of the
resulting package to copy in the above location: check it also to
enable hardware acceleration (disabled by default).