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The Concat KDF only supports the deriveBits method. It should also support the deriveKey method.
This is a point of confusion that we've discussed before. I guess some clarification is needed in the specification. Whilst there are both a deriveKey and deriveBits *methods* there is no 'derive key' *operation*. The procedure for the deriveKey method uses the same 'derive bits' operation as the procedure for the deriveBits *method*. The difference is that in the deriveKey case the returned bits are fed into the import key operation of the appropriate target algorithm wheras for the deriveBits operation the bits are returned directly.
The table lists methods, not operations. This should be fixed with the fix to 25625.