Siehe Links unter "Checks" auf dieser Seite: https://l10n.kde.org/
Zu den doppelten "&&": https://doc.qt.io/qt-6/qaction.html#text-prop
Certain UI elements, such as menus or buttons, can use '&' in front of a character to automatically create a mnemonic (a shortcut) for that character. For example, "&File" for a menu will create the shortcut Alt+F, which will open the File menu. "E&xit" will create the shortcut Alt+X for a button, or in a menu allow navigating to the menu item by pressing "x". (use '&&' to display an actual ampersand). The widget might consume and perform an action on a given shortcut.