How did it get a copy of 1984?

> [I] wasn't aware that 1984 is in the public domain in some countries.

ITYM "almost all countries"

According to my quick scan of https://en.wikipedia.org/wiki/List_of_copyright_duration_... I make it everywhere except:

Columbia, Equatorial Guinea, Spain (until 2030)
United States (until 2045)

Jamaica stands out with what looks like the longest period at 100 years from author's death, bit that's only for works created after 2003, so not applicable. The vast majority of the world goes with life+50 years in most cases, though numbers in the range 60-75 are fairly common, too.