Watermark

Watermark is a common name for a label in the bottom-right corner of the Windows desktop identifying the operating system version, which is most commonly seen in pre-release versions. Watermarks have originally been used by debug builds only, with the Windows 3.0 Debug Release 1.14 being the first known version to use one. They became more heavily used during the development of Windows 98 and Windows 2000, when they have become widely used to mark builds with an enabled timebomb.

A form of watermark is also visible when a Windows system boots in safe mode, which consists of the words "Safe Mode" (or equivalent in the current locale) placed in all corners and the operating system version printed out in top center. The safe mode watermark overrides any other forms of watermark, if any.