Jenkins Github Branch Source Plugin Failing with Github Token after today's Github auth changes

I am currently facing an issue with Jenkins <> Github integration due to today's Github auth changes deprecating user/pass auth and the current Github branch source plugin.

Deprecation info: https://developer.github.com/changes/2020-02-14-deprecating-password-auth/#removal

Plugin: https://github.com/jenkinsci/github-branch-source-plugin

Jenkins: 2.249.3
Github branch source plugin 2.9.1 (latest)
This jenkins install is private only (not public facing)
The repo being accessed is private (not public facing)
The Github token has full repo access

Issue:

The plugin forces user/pass auth which Github no longer accepts. The instructions state to put the TOKEN in the password field but it still complains after I've done that:

The API can't be accessed using username/password authentication

https://developer.github.com/changes/2020-02-14-deprecating-password-auth/#removal

Instructions state: "Only username/password credentials are supported" and instructs to add the Token in the password field (screenshot shows this)

The attached screenshot shows the debacle clearly:

enter image description here

Questions to ServerFault:

Am I entering the token wrong for the credentials? I've tried:
- a null user, with the token as the password
- The token as the user & pass
- The token description as the user, with the token as the password
Normally I would submit a Github issue to a developer about an app issue. However since there is no "Issues" component to submit issues to the plugin developer, I wanted to ask my question here, in case others have hit this.

Exactly same story here. Your post inspired me to dig deeper and I found a solution.

Go to the "System Configuration" (sorry, my Browser is set to german and I don't know the exact wording) and create new credentials for the GitHub server in "Secret Text" format. Use the Personal Access Token as secret and give it a description.

Verify with the "Test connection" button. It should print out the following:

Credentials verified for user your-cool-username, rate limit: 4876

GitHub API server settings

Now in the project it still forces me to use username/password credentials but it somehow seems to work with the global GitHub API settings we changed.

My username/password credential settings

There references in the plugins code about checkout via SSH (see here in the repo), but I couldn't find a way to use key auth. It puzzles me a bit that my solution works, I didn't expect that.

Edit: I actually found a checkout via SSH checkout option, not sure/expecting do better.