Use timestamps as a future-proofing method
Datetime is extremely informative by itself:
It is static compared to other data (e.g., title, IDs, language), not prone to change.
It quickly informs us if our stuff is outdated.
It lets us know of the related history.
It relates to other resources we refer to at the time.
To make future references easier to make, we could create two timestamps: one for the creation date and one for the modification date. This adds another point for useful comparison.
To start, we could interact with the File metadata. This lets you quickly evaluate whether the information is up-to-date without relying on the filesystem. It also lets you Maintain your own digital library with relative ease if your focus is on up-to-date information.