What happens under the hood during a sign-up from the blockstack browser?

What are the steps/operations that happen under the hood in the blockstack browser when a user signs up?
Can this be done from client-side code without redirecting to the browser?

I wrote a walk through of what happens here: https://www.larrysalibra.com/blog/blockstack-token-sale-voucher-registration-walkthrough/

As to specifically how blockstack authentication works with this forum, check out this post https://www.larrysalibra.com/blog/adding-blockstack-auth-to-discourse/