It's a subscribe popover so it doesn't count as an ad. I'm running uBlock and it didn't catch it.
Also the fact that I can’t block individual scripts (can I?) is a little irritating because often I just need one of the 50 scripts loading from a 3rd party domain to render the page but all of them load and execute.
source hostname {white spaces} destination hostname {white spaces} [request type {white spaces} [action]]