Almost everything in Tibetan Buddhism arrives from India. Teachers went south and west at enormous cost to collect it, translators worked for generations rendering it, and the schools trace their authority through Indian masters. Chod is the exception the tradition points to. Tibetan accounts hold that the practice originated with Machig Labdron in Tibet and was then carried back into India, where Indian yogins received it, which reverses the usual direction of the whole enterprise.
Her formation supports the picture. Before she was a teacher she was a chodpa in the older sense of the word, a professional reciter, employed to read the Perfection of Wisdom scriptures aloud, and she is said to have read at extraordinary speed. She then studied with the Indian master Dampa Sangye, whose Pacification teachings stand beside her own, and combined that inheritance with the scriptural material she had been reciting for years.
She was also a laywoman. She had a partner and children, one of whom continued her lineage, and she taught from that position rather than from a monastery. In a religious culture where authority normally came with ordination and with a male body, a woman who founded a lineage from outside both is a considerable anomaly, and the tradition has preserved her without much apparent embarrassment about it.