Code review comment for lp:~mbp/bzr/715000-more-fallbacks

Like John, I think _immediate_fallbacks_vfs (or maybe _immediate_vfs_fallbacks?) would be a little clearer, because repositories also have a fallbacks attribute. I'm ok with whatever name you decide on.

The patch itself seems to be just a mechanical rename of the variable, plus the merge of the bug 715000 fix, so that all looks good.