Show Process ID of Individual Web Page Tabs & Windows in Safari for Mac OS X
Anyone who develops just about anything for the web knows that following resource usage of a specific tab or window, or just tracking down an errant tab or window can be difficult, but Safari on the Mac has a hidden trick up it’s sleeve that makes it much easier; the ability to show web process IDs directly within the page and tab title of a Safari window.
This optional setting is aimed at advanced users and developers who have a reason to quickly see an individual webpage PID directly in a window title bar. For everyone else, it may be kind of useless, and a more user friendly approach is available in new versions of OS X, which allow users to see the URL of errant tabs and windows using a hover trick within Activity Monitor.