Shouln't default NDK be "the latest"?
The code comment would suggest that this is what was wanted at some point
if not version: version = 'r12b' # falls back to latest
...but I've always seen it stuck at 12
(Was this written at a time when 12 was "the latest"?)
This would be in line with what Android Studio encourages too, use the latest available versions of the tools.
Also looks like devs kinda expect to get "the latest" if they don't ask for a specific version: fdroiddata!5736 (merged)