UA: Mozilla/4.0 (compatible; Synapse)
Protocol: HTTP/1.0
Robots.txt: No
Host: Cox Communications (ISP), Comcast (ISP), Verizon (ISP) and others.
GET / HTTP/1.0" 403 4303 "http://www.flagcounter.me" "Mozilla/4.0 (compatible; Synapse)
Started at the beginning of December, 2017. A dozen hits per day, from various ISPs, all for root, seemingly to measure bandwidth.