I claim the ornamental design for a debris filter for a gutter, as shown and described.
FIG. 1 is a perspective view of a debris filter for a gutter showing my new design;
FIG. 2 is a top view thereof;
FIG. 3 is a bottom view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a back view thereof;
FIG. 6 is a right-side view thereof; and,
FIG. 7 is a left-side view thereof.
The broken lines depicting holes in FIGS. 1-3 are for the purpose of illustrating the unclaimed portions of the article and form no part of the claimed design. The debris filter for a gutter is shown with a symbolic break in its length in FIGS. 1-5. The appearance of any portion of the article between the break lines forms no part of the claim.