> Git doesn't need an equivalent of Mercurial branches and bookmarks, because git branches do everything both of those mercurial features do and more, in a far more lightweight and efficient manner contained in a clean, singular feature.

Not quite everything. Since Mercurial branch names are baked into the commit, if you wanted to know which branch a commit was originally part of, you can find out.

Git does not support this. If two branches have parent commits in common, it technically belongs to both branches.

There is a valid conversation to be had on if this feature is actually necessary or makes sense in the context of a DVCS, but git branches are not a full substitute for Mercurial branches.