Hi,
It seems you have the Fresh Player plugin installed (it's a different package than the flashplugin-installer). Do you remember how did you installed it? Maybe you added a repository for it to your install? Or maybe you added a plugin directly to Firefox?
In any case, this might help determine what package is providing it (in case it is being provided by a .deb package installed on your system):
Code:
apt-get install apt-file
apt-file update
apt-file search libfreshwrapper-pepperflash.so
Post the output of the last command here.