In the right pane you will see the Allow Extensions policy.
Navigate to: Computer Configuration -> Administrative Templates -> Windows Components -> Microsoft Edge.
Press the Windows Key + R together, type in gpedit.msc and hit Enter to open Local Group Policy Editor.
Method 1: Disable Extensions in Microsoft Edge Using GPO In this tutorial we’ll show you how to disable extension support and prevent users from installing any extension in Microsoft Edge on Windows 10. When your browser slows down or it doesn’t load webpage properly, a problematic extension may be the major cause. Browser extensions are third-party add-ons that provide extra functionality to Microsoft Edge.