I claim the ornamental design for a foot file blade, as shown and described.
FIG. 1 is a front bottom perspective view of a foot file blade showing my new design;
FIG. 2 is a front top perspective view thereof;
FIG. 3 is a rear bottom perspective view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a rear view thereof;
FIG. 6 is a left side view thereof;
FIG. 7 is a right side view thereof;
FIG. 8 is a top view thereof; and,
FIG. 9 is a bottom view thereof.
The dot-dash broken lines shown in FIGS. 1, 2, 4, 6, and 7 illustrate a boundary of the claimed design. The dash-dash broken lines shown in FIGS. 1-9 illustrate portions of the foot file blade that form no part of the claimed design. All broken lines and unshaded surfaces bounded by broken lines form no part of the claimed design.