jrb0001 
FYI, It should be the following list, aggregated from his Telegram Bot.
ali1.hk.dn42.strexp.net.
fmt1.us.dn42.strexp.net.
nyc1.us.dn42.strexp.net.
vul1.sg.dn42.strexp.net.
lax1.us.dn42.strexp.net.
lon1.uk.dn42.strexp.net.
ro1.ro.dn42.strexp.net.
lux1.lu.dn42.strexp.net.
tyo1.jp.dn42.strexp.net.
sol1.kr.dn42.strexp.net.
sea1.us.dn42.strexp.net.
las1.us.dn42.strexp.net.
van1.ca.dn42.strexp.net.
yzu1.tw.dn42.strexp.net.
or looking glass IPv6's rDNS results:
ali1.hk.bkb.strexp.net.
fmt1.us.bkb.strexp.net.
nyc1.us.bkb.strexp.net.
vul1.sg.bkb.strexp.net.
lax1.us.bkb.strexp.net.
lon1.uk.bkb.strexp.net.
ro1.ro.bkb.strexp.net.
lux1.lu.bkb.strexp.net.
tyo1.jp.bkb.strexp.net.
sol1.kr.bkb.strexp.net.
sea1.us.bkb.strexp.net.
las1.us.bkb.strexp.net.
van1.ca.bkb.strexp.net.
yzu1.tw.bkb.strexp.net.