This is to track work enhancing the current ML-KEM-768 code to also support the other NIST-specified variants, possibly via suitable re-structuring and definition of macros allowing "instantiation" of the three algorithm types. This is work basically proposed and pursued by @vdukhovni using the code in the "ml-kem" feature branch as source and target of activity, so any other work on this feature branch should take into consideration this ongoing activity.

(KAT) code to test all algorithm variants should be easy to add once #25938 has landed.