I think it varies from school to school based on what they think is important, but I wanna say that I learned about it in high school years ago. Of course, I also grew up in an area with a lot of Irish immigrants and descendants of Irish immigrants who were very supportive of the IRA. To the point of arms deals with the IRA being a thing with organized crime in the area. So I might know of it simply from living in Whitey Bulger country.