The ornamental design for a panel for a foldingknife, as shown and described.
FIG. 1 is a line drawing showing the panel for a folding knife according to the present invention applied to a knife;
FIG. 2 is a front elevation view of the panel for a folding knife according to the present invention;
FIG. 3 is a rear elevation view of the panel for a folding knife according to the present invention;
FIG. 4 is a front end view of the panel for a folding knife according to the present invention;
FIG. 5 is rear end view of the panel for a folding knife according to the present invention;
FIG. 6 is a top view of the panel for a folding knife according to the present invention; and,
FIG. 7 is a bottom view of the panel for a folding knife according to the present invention.
The ornamental design which is claimed is shown in the drawings. The broken line portions of the folding knife are provided for purposes of environment and form no part of the claimed design.