Trying this one again because I lost my marbles briefly in the first thread I made about this; SHA-2 is nice for file validity, but it is a minor inconvenience for the end-user to perform steps via other GUI programs or the command line to ensure file validity.
Having Caja index every file's SHA-2 fingerprint in the current directory and show them in list view (or at least, concatenated with means to expand in a tooltip on hover) would be nice for security-conscious users of mid-tier systems with SSD media, and for legacy systems that would be impacted rather heavily by the indexing process in some instances waiting for the procedure to complete would be better than exposing a system or network to a threat from a tampered file.
Also, having the journal ID (its journal in the Ext4 and NTFS partition formats independent of its file name and path) would be very nice to have on hand for users who make physical links, as the physical file and physical links would access the same node. Enhanced file interrogation tools available by default would be nice for users like me who love to use links a whole bunch where applicable, and knowing how these links apply; being technically intimate with the link chain would not only ensure security through information, but also make sure more technical users like myself are actually using the correct files for links to function as intended.
A functional power user example of this would be search via SHA-2; copy the ID from a website using that for validity and define an SHA-2 search, to get exactly that file as a search result, should the website for that particular file have current security fingerprint information and it exists on your local filesystem within defined scope.