This is the discipline basket — the Vinayapiṭaka, the monastic code: the rules by which the saṅgha governs itself, and the second-largest canonical sub-genre at 494 witnesses. But the striking thing about the Lanna vinaya is that a large part of it is not rules to be read but liturgy to be performed — the working ritual of monastic life.
On the scholastic side sit the classical texts: the Pācittiya (the offences requiring expiation), the Pārivāra (the appendix-digest), the Mahāvagga, and above all the great commentary, the Samantapāsādika (Samantapāsādika, Samanta) — the vinaya as a body of law and its exegesis.
On the performed side sit the ordination texts, and these are the living end of the basket: the kammavācā (Kammawa, Nangsue kammavācā) — the formal acts of the saṅgha — and the upasampadā ordination liturgy (Witthi uppasombot, "the procedure for higher ordination"). These are vinaya as spoken rite: the exact words by which a novice becomes a monk. That is why this sub-genre reaches across into the chanting liturgy — the kammavācā is a recitation before it is a rule.
Physically canonical — 93% palm-leaf (461 of 494) — and well-dated, 378 witnesses spanning 1537–1973. Like the sutta it concentrates at Wat Sung Men (199, ~40%) with Phrae and Lampang behind, the keystone-library effect again. Its language tilt is notably Pali-heavy: 199 monolingual Pali against 272 Pali-and-Lan Na — the formal legal and liturgical Pali needs no gloss to be recited correctly.