Unclear how to register an application, establish a client-id

[timcoote]

The wiki includes the comment (on https://github.com/google/gmail-oauth2-tools/wiki/OAuth2DotPyRunThrough):
"To use OAuth2, you must have registered your application through the Google APIs Console. Registration is explained in Using OAuth 2.0 to Access Google APIs."

Unfortuntately, neither of the links actually explains what needs to be registered where nor (presumably) how to obtain the 'client-id' token used in the examples on the page.

There is lots of stuff about setting up GCP accounts/projects, but nothing about getting a client-id. Additionally there is lots of documentation on how to use third party apps with the IMAP interface, but nothing (that I can find) on how authentication is now meant to work with IMAP on gmail for a simple program.

Isn't the withdrawal of an authentication mechanism quite a serious security event as it severely hits the availability (as in the mnemonic of Confidentiality, Integrity, Availability for Security) of the service?

[junyer]

gmail-oauth2-tools/python/oauth2.py

Lines 19 to 27 in aa0cdb9

	To use this script, you'll need to have registered with Google as an OAuth
	application and obtained an OAuth client ID and client secret.
	See https://developers.google.com/identity/protocols/OAuth2 for instructions on
	registering and for documentation of the APIs invoked by this code.
	NOTE: The OAuth2 OOB flow isn't a thing anymore. You will need to set the
	application type to "Web application" and then add https://oauth2.dance/ as an
	authorised redirect URI. This is necessary for seeing the authorisation code on
	a page in your browser.

Is https://developers.google.com/identity/protocols/OAuth2 more helpful? The wiki page hasn't been updated for six years. :(

[auspex]

This is still not useful. I get

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Error 400: redirect_uri_mismatch

after adding https://oauth2.dance/ as the authorised redirect URI. Possibly because the actual redirect is to https://google.github.io… but changing the redirect_uri in the URL to just https://oauth2.dance/ didn't help