Purpose of double angle brackets on the bash command line?

I'm trying to understand the following command:

user$ bash < <(curl -s https://something.com )

What 开发者_运维技巧do the < < do?

---

It's not < < but first < which means input redirection and then <( ... ) which means run the command inside the braces and make from that a file argument.

This looks to me quite equivalent as

curl -s https://something.com | bash