@shamsr that post you referenced was a long time ago… I suspect things changed after that since the only way to create a new token is via the App, and you must place said token into your sketch and re-upload it. 2nd EDIT - see further below for a workaround.
That all said, the Local Server is open sourced, but hacking the existing AUTH tokens (EDIT - in the App) is probably a programming level or two beyond the scope of this forums teaching.