/usr/lib/mozilla/plugins:
  => flashplugin-alternative.so
     - symlink to /etc/alternatives/mozilla-flashplugin
     - symlink to /usr/lib/flashplugin-installer/libflashplayer.so
        (size: 16460000 bytes, mtime: Sat May  6 11:58:00 2017)

/usr/lib/xulrunner-addons/plugins: