Using the github API, you can get a repository tree using (example done with CURL):
curl -H "Accept: application/vnd.github.v3+json" \
https://api.github.com/repos/{owner}/{repo}/git/trees/{tree_sha}
Assuming I have a repo called dev by owner NewCo, and I want to list the repo tree called XXXX, I would:
curl -H "Accept: application/vnd.github.v3+json" \
https://api.github.com/repos/NewCo/dev/git/trees/{tree_sha}
How can I find out the {tree_sha} value for tree XXXX? Any idea where can I find out this value?