From what I understand, git checkout changes the state of files in the current directory to what it was at a specific point in the tree. Hence it can be used to switch branches or to visit a previous commit.
Why was the name checkout chosen for this operation?
Is the analogy to "I'm going to go check this out"?
Is it to checking out books from the library?
I'm not asking whether the name is a good idea or not, or trying to offer judgement on that myself -- I'm just wondering what the historical origin of the name is.