Not sure. My information is largely based on observations made by people that live or have lived in BY. It's sort of common knowledge there that regardless which ISP or carrier you're on there's always one hop in common when traceroute'ing outside of the country.
As far as I can tell, virtually every network marked BY has a common transit or peer of AS6697 Republican Unitary Telecommunication Enterprise Beltelecom
Assuming the index of 144 total ASNs is correct marked BY, there are a handful of cloud providers/university systems (that I can count in one hand) that might have their own connectivity, but anything remotely advertised as eyeball goes through "Beltelecom" or "Business Network Ltd" (which in turn goes through "Beltelecom" or "National Traffic Exchange Center" (60330))
At a casual glance, look at how Beltelecom is one of the very, very few that has any international peers just based on the flags: https://bgp.he.net/AS6697#_peers
This is similar to to Iran's ITC/TIC (there's a handful of them, pop in 12880, 49666, 48159, etc. onto bgp.he for a quick look) where they are the in-between to international peers and domestic peers.
