The bones. Or possibly helpers, maybe attachments... Many places. Just look for lines like this:
XXXX: { x.xxxxxxx, x.xxxxxxx, x.xxxxxxxx },
With possibly a fourth x.xxxx for rotational values. Basically, you want to cut your filesize you need to remove all the keys in the sequence for every bone. Hence why I suggest Oinkerwinkle's Animation Remover. Fast and easy.