⺮ is the bamboo-top radical and reminds you that early Chinese registers, household rolls and books were all carved on bamboo strips bound together. Same radical in 籍贯, 书籍, 户籍 - all things written on bamboo originally.
phonetic
耤jí
to plough by foot (phonetic stem)
耤 supplies the sound jí. It depicts a foot pressing a plough (耒 + 昔) and originally meant the emperor's ceremonial spring ploughing - but in 籍 it works purely as a phonetic. Same series gives 藉 (rely on), 籍 (register).
