A phrommachat (พรหมชาติ; Lanna phromchat) is the household fortune-book — the illustrated almanac that reads a life from its birth-year. Its core is the twelve-year animal cycle: your year sets your fate-figure, your auspicious and inauspicious days, your marriage compatibility, the reading of your dreams and moles and the omens that bear on you. Where the holasat almanac is the astrologer's working table, the phrommachat is the popular face of the same science — the book a family actually kept.
The catalogue holds zero witnesses whose title names a phrommachat — every spelling checked (phrommachat, phromchat, phrom chat) returns nothing across the 6,959 manuscripts.
Inference — like lersi, this is a shape of absence, not a sign of unimportance. The phrommachat is one of the most reproduced divination texts in the Thai world; its total absence here says the two academic sources digitised so far simply did not hold one under that name, not that Lanna lacked the genre. It sits near the top of the want-list: maximum thematic weight, zero availability.
Tradition — the following is background from the wider Thai tradition, not from these manuscripts; treat specifics as orienting, not authoritative.