appName

The app name the SDK sends, in the X-Source header and at the head of userAgent, or null when there is none to send.

This is what goes on the wire, so a launcher label context derived appears reduced to a User-Agent product token: Jetpack (Debug) is sent as Jetpack-Debug, and a label with nothing a token can hold, such as one written entirely in kana, is not sent at all. A name from appIdentifier is sent verbatim, since that call rejects anything a token cannot hold.

Exposed so callers that make their own requests to Gravatar identify themselves the same way the SDK does, rather than deriving a second name of their own.