What is the difference between WebRTC-compatible browsers and endpoints?

A WebRTC browser is capable of executing the WebRTC API natively or by utilizing a browser plugin. See full list of browsers with native WebRTC support.

WebRTC-compatible endpoints (e.g., TURN servers, SFU, MCU, etc.) implement WebRTC-related networking protocols (e.g., SRTP, SRTCP, STUN, DTLS, etc), but not necessarily the API.