What do setUseWideViewPort() and setLoadWithOverviewMode() precisely do?

I am disappointed at the lack of documentation of WebView and related stuff.

(unless you think the following is propert documetation)

public void setLoadWithOverviewMode (boolean overview)

Set whether the WebView loads a page with overview mode

and:

public synchronized void setUseWideViewPort (boolean use)

Tell the WebView to use the wide viewport

So: What is "Overview mode" ? what is "Wide viewport" ?

ps: I tried to look for webkit related docs but could not find it.