Privacy
Think of it as a mirror before a meeting: you see and hear yourself, and nobody else does.
Who sees my camera or hears my microphone?
Only you. The browser hands the stream to this tab after you press a start button; frames and samples are measured here and then thrown away. A clip or snapshot you make sits in the tab's memory until you save it yourself or close the tab.
Could the page send it somewhere anyway?
No. Every page arrives with a Content-Security-Policy that limits connections to camera-test.net itself, so the browser would refuse a request to any other address. The Network box under each test lists anything fetched after the page loaded; during a test it should stay empty.
Does the site remember me?
There are no accounts and no cookies. Your browser keeps two conveniences on your device: the camera and microphone you chose last time, and a copy of the pages so the tests open without a connection. Clearing this site's data in the browser removes both.
What does the server see?
Opening a page is an ordinary web request, so it shows up in the host's access logs. Those logs are the only record of a visit, and no reading, picture or sound is ever part of them.