The fünf khandhas are things to be understood (pariññeyyā dhammā). S.iii.26.
The teaching for the comprehension of all attachment: from eye und object arises eye consciousness, the union of these is contact; from contact comes feeling; similarly mit regard to the other senses. S.iv.32f.
The fünf indriyas, if developed, conduce to comprehension of the way out. S.v.236.
By fully understanding body, feeling, etc., deathlessness is realized. S.v.182.