What are these API calls?

We’re using the JS SDK for exception reporting. I see some requests like this getting blocked by my ad blocker:

https://sentry.io/api/1393587/envelope/?sentry_key=xxxx&sentry_version=7

with a request payload of:

{“sent_at”:“2021-10-07T23:21:09.792Z”,“sdk”:{“name”:“sentry.javascript.browser”,“version”:“6.9.0”}}
{“type”:“session”}
{“sid”:“dec154670d52468fbdbc8aec5b6c2e69”,“init”:true,“started”:“2021-10-07T23:21:09.722Z”,“timestamp”:“2021-10-07T23:21:09.722Z”,“status”:“ok”,“errors”:0,“did”:“410efcf5-3513-4408-96af-70cb8e504be8”,“attrs”:{“release”:“d2417d4”,“environment”:“production”,“user_agent”:“Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.61 Safari/537.36”}}

What is this for? I don’t see an exception being reported here. Do requests like this count against our event quota?