Invoking Aria’s summarize feature will not work as currently described by Opera unless you are accessing it within the mobile version of the Opera browser. None of your suggestions are making any difference for the current desktop version of Opera. However, the issue has already been successfully addressed by BestCodes on the first response to my original post.
i.e. You can summarize a webpage using the Aria in-browser Command Line. From within the Windows based browser use Ctrl+/ (Cmd+/ on Mac) and then click the Tab key to switch to the Page Context environment. The Summarize Page feature will appear as an option once the Page Context prompt is displayed.
