The term cur refers to a mongrel dog. Originally the word cur referred to a certain English purpose-bred, short-tailed cattle droving dog known only from historical records, the cur dog, but in modern usage it applies to any mongrel.
The ICO file format is an image file format for computer icons in Microsoft Windows. ICO files contain one or more small images at multiple sizes and color depths, such that they may be scaled appropriately. In Windows, all executables that display an icon to the user, on the desktop, in the Start Menu, or in Windows Explorer, must carry the icon in ICO format.