[JdeBP]

I would be surprised if has not. There have been lots of tools over the years where the idea was to present a command-line interface compatible with Sendmail's message submission mode, and hand the mail over to a smart host, possibly not using anything like SMTP.

I predict that someone will be asking for the -t option to be supported here. (-:

[tonymet]

it works implicitly . gmail api reads the headers for BCC / to: etc. I'll see about improving the command line args and usage