In general Buddhist usage, the term "treasury of the Dharma" refers to the written words of the Buddha's teaching collected in the Sutras as the middle of the Three Treasures of the Buddha, Dharma, and Sangha.
Dahui Zonggao, the famous 12th century popularizer of koans in Song Dynasty China, wrote a collection of kōans with the Chinese title Zhengfa Yanzang (正法眼藏).