For when you really need to know the difference between two FileMaker files: fmdiff
fmdiff version 3 has just been released.
From the developer:
FMDiff 3 is not just another simple update, it's the sum of more than one year
intense development and testing. More than 1,200 changes have been applied,
and the program code had to absolve 1500 unit test before being implemented.
Of course it covers all functions and script commands, including those of
FileMaker Pro 13. Solution folders can be selected via button or menu, instead
of dragging only.