You can now get a list of changes in Bugzilla between any two particular points in our development using Github's difference interface. Select the before and after points you want using the controls at the top of the page. By default, the controls list every branch, but not every tag.
Every Bugzilla release (and there are many) is tagged with a name equal to the string "release-" followed by the version number. So, for example, to see the differences between 4.4.8 and 4.4.12, you would end up here.