Does Opera have config page like Firefox browser?

Solution 1:

I found opera-mac-internal-pages-and-more that contains lots of information that you could try.

I quote some of them here:

opera://about/                  About Opera, Update check, Install information
opera://settings/               Manage browser settings
opera://themes/                 View and manage Opera themes and wallpapers
opera://settings/passwords/     View and manage passwords
opera://bookmarks/              View and manage bookmarks
opera://extensions/             View and manage installed extensions
opera://history/                View and manage browser history
opera://downloads/              View and manage downloaded files