If anyone can get access to PDFs that would be much appreciated,
but I hate to disappoint, but looking at the list of volumes briefly they are quite common texts transmitted in various Northern vernacular languages such as Lao, Lanna, Shan etc
The volume on Archive is the text that has been briefly described by Donald Swearer, I think in Becoming the Buddha but would need to check. It’s a type of chronicle called a Tamnan in Thai, showing how the Buddha visited various locations, made predictions and gave out relics etc and why different places have such name usually related to the Buddha’s visit.
Obviously each manuscript will reflect the local culture. For a taste of what these texts are like:
https://ecommons.cornell.edu/items/101d99b8-dfa7-43aa-8b9b-0fc343fb08ab
(On the most famous Stupa in North East Thailand that was probably a Shiva shrine 1200 or so years ago…)
Other texts mentioned include the Sudhana Manohara Jataka, the Laws of King Mangrai and probably some Kammatthan Boran meditation texts, the Perfection of Wisdom sutta (which is the 30 parami of the Pali tradition) etc
For an example of a similar style of Jataka from same cultural area: OPUS 4 | Language, Orthography and Buddhist Manuscript Culture of the Tai Nuea - an apocryphal jātaka text in Mueang Sing, Laos
And for a whole set of related texts, with a very similar style, i.e. the odd Pali word interspersed in a vernacular text. Including typical Anisong, that is merit making sermons, a local telling of the Vesantara Jataka and even a translation of a version of the aforementioned Pannaparami Sutta:
The Tham Vessantara-Jataka: A Critical Study of
If anyone can get it in any form, I know some who would like to have, though perhaps only somewhere like the University of Chiang Mai or Mahidol have space for the 100 volumes!