Restore previous Safari version from .SafariArchive.tar.gz

Did that new Safari update break something? Want your old version back?
Simple. Thanks to Apple’s prescient yet secretive engineers, there’s a way.
Let me show you.

When Safari does an upgrade it saves the previous version in this location:
/Library/Application\ Support/Apple/.SafariArchive.tar.gz

To restore we just need to tell tar to expand the archive to the root folder:
sudo tar -xvf /Library/Application\ Support/Apple/.SafariArchive.tar.gz -C /

To be complete, delete the receipt from /var/db/receipts, in this case it is Safari 5.1
sudo rm -rf /private/var/db/receipts/com.apple.pkg.Safari51SnowLeopard.*

Reboot. (since we’ve just replaced a whole bunch of public and private frameworks the OS uses)

Done.
(Whew. This will fix the early Safari 5.1 adopters at work who now can’t use our Java based timesheet app since upgrading!)