r18-a2-n-u2r-s200
Learning base for learn-then-unlearn: final native checkpoint (pt_native_v3 step 21457) + 200 steps of 2012-text NPO, retain KD+CE on 2010-2011 news, hard-weighted known loss and king-2025 distilled QA SFT. Dev known 0.959-0.973 (above parent), leak 0.27.