When using the path parameter for github boards (I used a data folder), the data.txt file is created inside the data folder. Which is fine, the problem is with paths inside the data.txt file that are not relative to the data folder as I expected.
See repo in data folder here
These are the contents of the data/data.txt file
I believe one data.txt file should be placed in the root of the repo, but also there should be a data/data.txt file with relative paths to all pins inside the data folder.