Did anyone find and remove Kiritsugu's explosives?
According to Fate Complete Material III: World Material - Record of Heavens Feel - Holy Grail War: History of the Holy Grail War, p.007


  2010s - The taking apart of the Holy Grail War.
  Ten years after the Fifth War. Lord Emelloi II (real name, Waver Velvet. One of the Masters of the Fourth War) arrived in Fuyuki and together with the head of the Tohsaka line, set out to completely take apart the Great Grail. The Association was planning on bring back the Greater Grail, so the two sides were completely opposed. After the end of the great turmoil of the same magnitude as the Grail War, the Greater Grail was completely dismantled. The Grail Wars of Fuyuki came to a complete conclusion here.


Since the Greater Grail is connected to the leylines, a thorough analysis of them would take place before dismantling. Remember that Waver was able to locate a Caster servant's lair as a teenager, he should be able to discover whatever Kiritusugu set there, this is just speculation though. At the very least, the meddling with the leylines should be taken care of, but I don't think there's any mention anywhere about the explosives' fate.