namespace: http://www.mozilla.org/metrics

<log/>
Description:
<log> is the root element of the metrics report document.

<startup/>
Event: Application startup.
Attributes:
  time: The time at which the event occurred, in seconds since the epoch (int).

<shutdown/>
Event: Application shutdown.
Attributes:
  time: The time at which the event occurred, in seconds since the epoch (int).

<windowcreate/>
Event: A new DOM Window (toplevel or child window) is created.
Attributes:
  time: The time at which the event occurred, in seconds since the epoch (int).
  id: The id of the new window (int).
  chrome: Whether the new window is for a chrome docshell (bool).  If not specified, assumed to be false.

<windowopen/>
Event: A toplevel DOM Window is opened via window.open().
A <windowcreate/> for this window will preceded this event.
Attributes:
  time: The time at which the event occurred, in seconds since the epoch (int).
  id: The id of the window that was opened (int).

<windowclose/>
Event: A toplevel DOM Window is closed via window.close() or user action..
Attributes:
  time: The time at which the event occurred, in seconds since the epoch (int).
  id: The id of the window that was closed (int).

<windowdestroy/>
Event: A DOM Window (toplevel or child window) is destroyed.
Attributes:
  time: The time at which the event occurred, in seconds since the epoch (int).
  id: The id of the window that was destroyed (int).

<load/>
Event: A document has been loaded into a DOM Window.
Attributes:
  time: The time at which the event occurred, in seconds since the epoch (int).
  window: The id of the window where the document was loaded (int).
  origin: The event which initiated the load (string).  Legal values are:
      typed: The document URI was typed (or pasted) by the user.
      link: The user followed a link to the document URI.
      session-history: The user used back/forward navigation to load the document.
      reload: The user used the reload button or keyboard shortcut to reload the document.
      global-history: The user loaded the page by selecting it from their global history.
      bookmark: The user loaded the page by selecting it from the bookmarks menu, bookmarks toolbar, or bookmarks management UI.
      script: A script executing on a page loaded the document.
      refresh: A meta-refresh loaded the document.
      external: The document URI was passed in from an external application.
      other: Any load which does not fall into one of the above categories.
  loadtime: The time from the initiation of the load until the document is complete (which includes all images, stylesheet, etc) in milliseconds.
  bfCacheHit: Whether the document presentation was loaded from the session history cache (bool).  If not specified, assumed to be false.