Yesterday I got the message that my current version of Firefox could not categorize as safe my add-on.
This morning there was an new update to Firefox 66.0.3 and I thought the problem was fixed, but it was not fixed.
In search of the enabling of my add-ons (I only have two) I saw that you can download this:
Then you must go to the your URL (that is your Internet address where you find this in most cases: https://www.xxx.com) or click on the shortcut CTRL+L.
You must enter:
then you see an entry with a check box:
Enable add-ons and go the button (right side): Load add-ons
Then opens a new window and you go the folder where you have saved the downloaded file with the extension .xpi.
Click Ok and then the .xpi file is loaded.
It takes a few seconds and Firefox changes to the settings that you had before the error messages.
In many German forums a lot of people wonder why it is so very difficult to install it. I think that they never have been working in a Level 1 IT Support. They cannot image that a lot of people does not know something about IT.
I think that they should work for 6 months in a Level 1 support, daily, 8 hours per day, then they have a clue that IT is not for every one easy.