The ornamental design for an exhibitbracket, as shown and described.
FIG. 1 illustrates a design for an exhibit bracket, in perspective view;
FIG. 2 is a right side view, thereof;
FIG. 3 is a left side view, thereof;
FIG. 4 is a front view, thereof;
FIG. 5 is a rear view, thereof;
FIG. 6 is a top view, thereof; and,
FIG. 7 is a bottom view, thereof.
All broken lines represent structure or features that form no part of the claimed design. Specifically, the dash broken lines form portions of the exhibit bracket that are unclaimed and/or portions of environmental structure.