/usr/lib/mozilla/plugins:
  => librhythmbox-itms-detection-plugin.so
        (size: 6096 bytes, mtime: Sun Apr  5 13:24:25 2015)
  => flashplugin-alternative.so
     - symlink to /etc/alternatives/mozilla-flashplugin
     - symlink to /usr/lib/flashplugin-installer/libflashplayer.so
        (size: 19264896 bytes, mtime: Tue Sep 22 23:08:40 2015)

/usr/lib/xulrunner-addons/plugins: