where did you find your link?
when you use multiple search engines, it throws different algorithm's and a broader spectrum of chance to find interesting stuff
mine was a straight yandex find
F-2015-00940
Looked at gov, irs stuff that could yield, not much of a digger but took a stab at seeing what is out there
https://yandex.com/search/?text=F-2015-00940&lr=202
https://foia.state.gov/_docs/FOIALogs/FOIA_Logs_2015_C06360166.pdf