A major revamp of this website is coming soon, but for now, I wanted to provide a quick update. The WordPress 5.8 brought a significant change to the way widgets are edited in the Customizer and the Appearance - Widgets page. By default, the widgets use the Block Editor (Gutenberg) instead of the classic interface where widget boxes on the left are dragged into widget locations on the right.
For those who prefer the classic widget experience, we have installed the Classic Widgets plugin. Site administrators can enable this plugin for all users on their individual sites.