CLAIM The ornamental design for a graphical user interface for a display screen or a portion thereof, as shown and described.
The FIGURE is a front view of a graphical user interface for a display screen or portion thereof showing our new design.
The broken line showing of the display screen or portion thereof is not part of the claimed design.
The OpenPeak trademark in the upper left corner of the FIGURE is the property of OpenPeak Inc. The Dish Network trademark on the left side of the FIGURE is the property of Dish Network L.L.C. Trademarks are the property of their respective owners.