Recognize timestamps up to year 2286
#7610 (closed) added support for converting Unix timestamps to human-readable dates in the right-click menu.
The supported range goes from timestamp 1B (year 2001) to 2B (2033).
Now that Ubuntu has put a lot of effort into making 24.04 year 2038 compliant (64-bit timestamps even on 32-bit archs), I think it's time we catch up, too :)
The attached fix extends the range to 10B (year 2286).
While at it, can we again consider enabling this by default please (#7905)?