There are three options:

• If you're writing the App for your own use, you don't have to publish - simply make you gmail account expemental.
• If you publish it, anyone can use it, but before it's authorize they'll this alert warning.

And here is the tricky part. When I first wanted to authorize it told me I don't need to. But I wanted to, because I don't want the scary warning ! And so the third option is:

• To authorize your app, add an Icon - and then publish. You'll need to add web site, privacy and terms of usage web pages, and then you'll get the following note from goog:

  The Trust and Safety team has received your form. They will reach out to you via your contact email if needed. The review process can take up to 4-6 weeks. Expect the first email from our Trust and Safety team within 3-5 days. Your last approved consent screen is still in use. Learn more