Google appears to be removing the Google Cast name and switching it back to the original Chromecast moniker. As noted by Android Police, Google has already renamed the @GoogleCast Twitter account back to @Chromecast, and the Google Cast website now describes Google Cast as “Chromecast built-in.”
The Google Cast name was originally introduced when Google began expanding Chromecasting to other devices; earlier this year, Google renamed the Chromecast app to a matching “Google Cast” name. The name change was a nod to the fact that there were now lots of non-Chromecast products out there that had Casting built in, a decision that seemed to make sense at the time.