This opens the opera mini's power user settings page where you can tweakmany browser setttings like the timeout, whether the browser should make phone number clickable and lots more.
It's quite a handy tool for my fellow web developers. It displays the html code setup of any page (i.e it shows the source code of any page you are viewing).
It lets you know how much memory the cache memory is chewing up in your mobile phone.
It helps you view information concerning the opera mini proxy server in usage.
It displays opera mini server and client properties.
It helps you to navigate to the opera mini's mobile friendly formatted feedpage.
Displays the copyright and license information for third party softwares used in the browser.
It clears all stored cookies which can be helpful to clear any tracking analytic program.
It is used to reload a page, though pressing #0 also does the same function and is easier to access and remember.
The O codes
o:, - opens search page adding menu.
o:/ - opens option to add search engine.
o:! - opens page option to clear cookies.
o:$ - shows the Failed to connect to the internet page.
o:~ - gives option to change the screen orientation of your opera mini.
o:d - opens page to add bookmark.
o:h - opens the about opera page.
o:m - opens the search engine manager page.
This last two work only on Opera 4.n series
o:A - takes you to your opera start page.
o:Z - Opens your bookmarks.
If this post was of help to you, please click the like button or share button. I would always keep you updates if I get to more.