Opera

Opera supports the exact same format for setting cookies as Internet Explorer and Mozilla Firefox. This means that Opera will be able to accept all cookies that work with these browsers. Cookies are stored in the file named cookies4.dat located in the user's Opera profile folder (on Linux known as .opera, on Macintosh called Opera Preferences). It is not possible to edit the file cookies4.dat by hand in order to remove unwanted cookies from your hard drive, but you can use Opera's server manager (go to Tools > Preferences > Advanced > Cookies, click "Manage cookies").

Web developers should note that Opera does not store cookies sent from files loaded with the "file://" protocol, that is, local files on your hard disk. The reason is that such cookies are considered a privacy risk.