Having mounted the Recovery HD1, I MD5'd the Safari binary from the BaseSystem.dmg
and MD5'd the Safari binary from my OS X Mavericks 10.9.1 install:
/Volumes/OS\ X\ Base\ System/Applications/Safari.app/Contents/MacOS/Safari
:669623eb8c35daf0a1a90b4895943723
/Applications/Safari.app/Contents/MacOS/Safari
:668065167a8b3b9ad3034bdba400a9dd
What's been changed in Safari.app on the Recovery HD?
1 Mounted using:
diskutil mount Recovery\ HD && hdiutil mount /Volumes/Recovery\ HD/com.apple.recovery.boot/BaseSystem.dmg