The product team confirmed that the plugin mentioned in your post is not from F-Secure. They have filed a report for that one.
Thanks to you for highlighting this to us!
As far as I see this add-on, this is not the official add-on for the F-Secure Safe Search. I will bring this to the attention of the SAFE Search product team.
No one has helped in any way!
Could you please brief us on your issue and is it related to this post here?