/usr/lib/mozilla/plugins:
  => libjavaplugin.so
     - symlink to /etc/alternatives/mozilla-javaplugin.so
     - symlink to /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so
        (size: 630160 bytes, mtime: Sat Apr 16 21:00:55 2016)
  => flashplugin-alternative.so
     - symlink to /etc/alternatives/mozilla-flashplugin
     - symlink to /usr/lib/flashplugin-installer/libflashplayer.so
        (size: 16464096 bytes, mtime: Thu May 11 07:45:41 2017)

/usr/lib/xulrunner-addons/plugins: