@leocg I don't say that Opera should have this (not my suggestion) but I don't understand your confrontation regarding this function.
For example Vivaldi has this panel in sidebar, Edge also has something similar (Collections where you can leave notes), so why Opera can't have the similar feature?
And I already provided possible explanation: the same UI and the option support from Opera (not from extension's author who can abandon it and leave outdated)
Anyway, this is suggestions thread, the user posted his suggestion and explained what for he needs it, not clear why moderators require more explanation. Let Opera decide if this is a really reasonable suggestion or not and ask extra details. But I doubt that Opera will even notice/read it.