SubValues

SubValues[f] gives a list of transformation rules corresponding to all subvalues (values for f[...][...]...) defined for the symbol f.

Examples

Define and retrieve subvalues:

f[x_][y_] := x + y;
SubValues[f]
(* {HoldPattern[f[x_][y_]] :> x + y} *)

Check subvalues of a symbol:

g[a_][b_][c_] := a*b*c;
SubValues[g]

Please visit the official Wolfram Language Reference for more details.