What does GitHub for Windows/Mac “publish” do?

Question

Like in What does GitHub for Windows' "sync" do?

What does GitHub for Windows/Mac “publish” do?

Does it push the branch to my origin?

Answer 1

Does it push the branch to my origin?

Yes, but if you don't have an origin yet, it will ask you for the kind of remote repo you want to create.
(create... on GitHub of course)

See "Push your code to GitHub.com"

Click the “Publish” button in the upper-right corner and GitHub Desktop will ask you what kind of repository to create:

• Public repository — Anyone can see a public repository, but you choose who can commit (make changes) to it. You can create as many public repositories as you want on GitHub.com for free.

• Private repository — By default, only you can see a private repository. You choose who can see and commit to this repository by adding collaborators. Private repositories require a paid subscription on GitHub.com.

Then the button transforms to a "Sync" button.