Confusion about "browser-instance-specific"

[ckr]

Hello
I am reading the document of GeneralUsage. In the chapter "Application Structure",

Every CEF3 application has the same general structure.
Provide an entry-point function that initializes CEF and runs either sub-process executable logic or the CEF message loop.
Provide an implementation of CefApp to handle process-specific callbacks.
Provide an implementation of CefClient to handle browser-instance-specific callbacks.
Call CefBrowserHost::CreateBrowser() to create a browser instance and manage the browser life span using CefLifeSpanHandler.

I have some confusion about "browser-instance-specific"
Taking Google Chrome browser as an example：
When I open the Chrome application on the desktop, there is currently one browser process and one renderer process. (let's just ignore processes other than the browser process and renderer processe)
And when I open a new website in a new tab, it triggers the creation of an additional renderer process.
So for now , i have one browser process and two renderer processes.
In this scenario, what does 'browser-instance' represent?

[magreenblatt]

“browser-instance-specific” means callbacks for a specific CefBrowser instance.

[ckr]

“browser-instance-specific” means callbacks for a specific CefBrowser instance.

1. In the scenario above, how many CefBrowser instance exist?
2. When accessing different sites, is there a one-to-one relationship between CefBrowser instances and tabs

[magreenblatt]

There would be one CefBrowser instance per tab. Any navigation in a tab stays in the same CefBrowser instance.