The ornamental design for a brim for headwear, as shown and described.
FIG. 1 is a perspective front view of a brim for headwear.
FIG. 2 is a bottom view thereof.
FIG. 3 is a front view thereof.
FIG. 4 is a rear view thereof.
FIG. 5 is a left side view thereof.
FIG. 6 is a right side view thereof.
FIG. 7 is a top view thereof; and,
FIG. 8 is an enlarged detail view taken from line 8 in FIG. 1.
The broken line showing of the headwear illustrates the environment of the claimed design and forms no part thereof. The broken lines within the brim depict portions of the brim for headwear that form no part of the claimed design. The broken lines indicating the enlarged detail form no part of the claimed design.