Thank you for your interest in supporting with administrative boundaries.

As these are usually very hard to map from “the ground”, they tend to be very hard to verify. We have to rely on sort of official data sources where often the license has compatibility issues.

License needs further checks.
geoBoundaries seems to just collect boundaries from various sources. The ADM2 of Thailand contains this note:

Boundary Source(s): Royal Thai Survey Department, OCHA ROAP
Canonical Boundary Type Name: districts
License: Creative Commons Attribution 3.0 Intergovernmental Organisations (CC BY 3.0 IGO)

on the linked source they seem to have data down to tambon level.:
https://data.humdata.org/dataset/cod-ab-tha?

They document:
License: Creative Commons Attribution for Intergovernmental Organisations
Acquired by ICRC from the Royal Thai Survey Department by the and made available to OCHA.

Specifically:

Under the CC BY-IGO license, you are free to share (copy and redistribute the material in any medium or format) and or adapt (remix, transform, and build upon the material) for any purpose, even commercially. The licensor cannot revoke these freedoms as long as you follow the license terms. The license terms are that you must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. Additionally, you may not apply legal terms or technological measures that legally restrict others from doing anything the license permits. When the Licensor is an intergovernmental organization, disputes will be resolved by mediation and arbitration unless otherwise agreed.

I am no lawyer. I would guess that we might be able to fulfill the attribution requirements by linking it on the Contributors page. Would be nice if someone more knowledgable about the CC-BY-IGO license could comment on the specific requirements and compatibility.

I have a tendency to say we should fetch the data then from the main source.