A genelogy program says I need to add a FireFox Extension FFClickOnce. I cannot seem to find this extension. Any pointers?

FFClickOnce is a Firefox extension that enables OneClick
loading of applications by the .NET environment of Microsoft
using the Firefox Browser.
This extension has not been adapted to K-Meleon up to now,
and I don't know of existing plans to do that.
The Microsoft .NET environment would also have to be
installed beforehand to use a ClickOnce extension.
In my opinion it would always be risky to load an unknown
application from the web by one click without the possibility
to check what happens, so I would be careful.

Fred