Same as undo, when undo is exhausted, it redoes. Some software (such as KDE) allow their shortcuts to be changed, and the below list contains the defaults.
For example, in a non-English version of Windows, the Edit menu is not always bound to the E shortcut. Some of the combinations are not true for localized versions of operating systems. Not all applications follow (all of) these conventions, so if it doesn't work, it isn't compatible.
Whether such commands are implemented (or not) depends on how an actual application program (such as an editor) is written. Many shortcuts (such as Ctrl+ Z, Alt+ E, etc.) are just common conventions and are not handled by the operating system. Whether used as a matter of personal preference or for adaptive technology, the pervasiveness of common conventions means that a meaningful comparison of keyboard shortcuts can be made across various widely used operating systems. Their use is pervasive enough that some users consider them an important element of their routine interactions with a computer. Keyboard shortcuts are a common aspect of most modern operating systems and associated software applications.
