What does hg bookmark mean in this context?

I am reading through Chris's excellent article about working with git and pushing to BitBucket. With the instructions presented there, I managed to get everything working. However, I would like to understand what happens开发者_StackOverflow中文版 there. I'm specifically interested in this line:

hg bookmark hg/default -r default

I understand that this creates a bookmark named hg/default, but why does it have default as a revision? What does this mean?

The -r (or --rev) tells Mercurial that the bookmark should be set to the head of the default branch.

Using this technique, you set a bookmark to a revision other than that of your working copy.

This is documented in hg help bookmark.

If no branch name is set manually, Mercurial assigns the branch name default.

default is the name of a particular path of changes (change sets) and in this case it is used to create your bookmark.