Added info on how to find the browserWSEndpoint (#780)

docs/api.md

@@ -228,7 +228,9 @@ Closes browser with all the pages (if any were opened). The browser object itsel
 - returns: <[string]> Browser websocket url.
 
 Browser websocket endpoint which could be used as an argument to
-[puppeteer.connect](#puppeteerconnectoptions).
+[puppeteer.connect](#puppeteerconnectoptions). The format is `ws://${host}:${port}/browser/<id>`
+
+You can find the `webSocketDebuggerUrl` from `http://${host}:${port}/json/version`. Learn more about the [devtools protocol](https://chromedevtools.github.io/devtools-protocol) and the [browser endpoint](https://chromedevtools.github.io/devtools-protocol/#how-do-i-access-the-browser-target).
 
 ### class: Page