It means those travelers whose provisions have ended. As mentioned in Fatawa A’alamgiri, Vol. 1, Pg. No. 188.
In all the aforementioned avenues of Zakaat, the 4th avenue is abrogated and the 5th one is not at all possible in these times. It is valid to spent Zakaat in any of the remaining 6 avenues. It is not necessary to spend it in all 6.