Few things I can't figure out from a tweet.

1 - Is Lambda going to train engineers already hired at Amazon and is just going to provide an onboarding bootcamp for new hires? Doesn't sound like a bad idea considering Amazon's scale and the amount of internal tooling they must have.

2 - Is Lambda going to supply bootcamp-grads programmers to Amazon?

3 - What do they mean by "Back-End"? Is it Software Engineering roles or back-end customer service/SRE they are training them for?