The phrase "startling revelation" means a surprising and unexpected piece of information or knowledge that is revealed. It describes something that is shocking or astonishing to learn. Full definition
The good news is that startling revelation happens less than you think. (lawyerist.com)
The Mayor of Kumasi Kojo Bonsu has made startling revelations about the 46,000 dollars that was allegedly stolen from former Sports Minister Mallam Ali Yusif Issa in 2001. (ghanapoliticsonline.com)
Desmond Okotubo, described by the police as a senior member of Waney's gang, made startling revelations about his boss. (punchng.com)