Thon (ถอน — "to withdraw, pull out, annul") is the rite of un-doing: the recited ceremony that lifts a curse, dispels inauspiciousness and — above all — neutralises the danger left behind by a bad death. The catalogue holds 29 witnesses whose titles name it, and read together those titles draw the rite's purpose with unusual sharpness. Two words recur across them: _tai hong_ (the untimely, violent death) and _khuet_ (the taboo, the polluted or inauspicious). Thon phi tai hong, Thon khon tai, Thon tai ok luk (death in childbirth), Thon samanen tai (a novice's death); Thon sappa khuet (all inauspiciousness), Thon ban, Thon huean (of house and home), Kalakini (misfortune). The rite's verbs are _song_ — to send off, to dispatch — and _sut / suat_ — to recite.
Inference — the split in the catalogue between magic & ritual (14) and liturgy & chanting (7) is not confusion but the rite's actual nature: thon is magic performed as recitation. You do not draw it or brew it; you say it, and the saying is what withdraws the harm. That is why the same title so often pairs sut thon with katha and nyan — the spoken annulment carried alongside spell and diagram.
Tradition — the following is background from the wider Tai–Lanna tradition, not drawn from these manuscripts. In Thai and Lao folk belief a _tai hong_ death — violent, sudden, unnatural: accident, murder, drowning, and especially death in childbirth — is the most dangerous of all. The spirit of such a death does not settle; it becomes a _phi tai hong_, a restless and hungry ghost, and its danger can cling to the living, the house, even the village. Ordinary funerary merit is not enough; the death must be actively withdrawn — its pollution pulled out and sent away — before normal life can resume. _Khuet_ (ขึด) is the Lanna name for that broad field of taboo and inauspicious pollution: acts, places, times and events that carry misfortune and must be ritually cleared. Thon is the working answer to both. (This describes a well-attested belief-complex in general terms; I am not citing a specific source, and local practice varies.)
Inference — seen through that lens, the catalogue's title-lists stop looking like a jumble and become a taxonomy of dangerous deaths a practitioner had to be ready for: the layperson, the woman in childbirth, the novice, the monk, the ghost already gone bad — each with its own thon. The manuscript is a professional's index of crises.
Overwhelmingly a working paper technology — 26 mulberry-paper against just 3 palm-leaf — and almost entirely Tham Lanna (27 of 29). It leans research-priority (17 of 29, 59%) and clusters hard in Nan (16), with Lampang (6) and Phayao (4) behind — the vernacular-temple pattern, well away from the canon's Wat Sung Men gravity. Barely dated (4 witnesses, 1907–1937): late paper, in active use.