I installed Catppuccin for GitHub File Explorer Icons and while it does what it advertises, in Orion, it also permanently shows up in the right-click context menu:
This does not happen on Firefox and Chrome. Instead, the same "Enable ..." shows up in the extension-specific context menu on the top right of the browser toolbar:
This is happening with the Firefox extension installed in Orion. I haven't tested the Chrome extension in Orion yet.
I don't expect the extension to have any presence whatsoever in the right-click context menu.
Version 0.99.130.2-beta (WebKit 621.1.2.111.4)