In the Extensions Panel there is currently no way to open an installed extension's page on the Chrome or Firefox store. The name of the extension and perhaps its icon could be turn into links that would open the relevent page on the relevant store (depending where you installed it from).
Alternatively an "Open Extension Page" button or similar could be added to the Extension Panel.
Presumably Orion knows the URL for each extension because its able to check it for updates. So it's just a matter of making this URL accessible to the user as well.
This would be really useful for quick access to check for version notes, report bugs, and such. Currently you have to navigate to the appropriate store and search for the extension manually. (Though some extensions helpfully have a link in their popup for such purposes).