Sorry for delay in this answer, dear Philipos.
I was looking for a e-book but from Mexico the download is impossible. I use a proxy to get access to such volume.
In the first pages, the Dedicatory indicates that this is a 'posthumous' volume, done under the general plan/idea of the work started by Mai, trying to accomplish the incomplete tasks.
By this reason, the date of publishing is very late -1871, around 20 years after the first imprint-, and was realized by Josephus Cozza, who seems to be working in some of the earliest editions of the
Vatican Codex, around the 1868 year.
I'm trying to update the NPB adding this late volume, which is by itself, a great and magnificent notice.
Salus!
Francisco.