What is Pull actually doing under the hood?

If what I'm asking could've been found on the website, I apologize. I did see some indications that the Pull button in Working Copy does a fetch and a merge, but it seems like it's doing more than that. I seem to have fewer conflicts in Working Copy when I've edited the same files in the remote origin and locally. When I do that with other git clients I'll get errors that pulling might overwrite some of my files, but I don't get that in Working Copy. It seems like Working Copy might be rebasing and auto-stashing. Am I on the right track, or is it more nuanced than that?