[REQ] New button in CBC

[XPEHOPE3KA]

CBC=Compare By Content.

I want a button to show only the largest common substring within the two files (or its size in characters). That can be very useful when compareing media files, one (or both) of which is cut via some utility without reencoding.

Ok, I know that it has nothing with file manager development, will eat some place on the screen, etc.
And I don't know if there is a nonexponential algorithm to find such substring.
Now time to ask: anyone else need this feature?