Thanks for your reply.
However the link is leading to a page which refers to the “old Edge Browser”!
There I had no problem installing the extension.
I am having problems trying to install the extension for the new Microsoft Edge Chromium Browser!
By the way, I learned that the extension installation for Edge Chromium Browser works fine with UiPath Studio Version 2020.3.0!
However, since my company does not yet allow to upgrade from UiPath Studio Version 2019.10.4 to UiPath Studio Version 2020.3.0, I am searching a solution for version Studio Version 2019.10.4.
Any further suggestions?