Observing the textual differences between the British Library's Add MS 10027 and the RRIISS' "Fragmenta Historiae Pisanae," the first and arguably most important difference, which has the greatest potential to influence historical research going forward, is is the fact that the RRIISS version is missing twenty-four lines which appear on f. 39v of the British Library's manuscript.
Vanni di Nuccio di Lanibardo
Neruccio suo figliuolo e i fante suo
Coscio e Lambando fratello de stesso Vanni
Coscio di Tecco e uno suo nipote
Nocco di Lupo pelliccia
Vogiunta panino Maghinardo
Vanni di Lando coraio
Anco lo suo figluolo
Lo filuolo di Cierino
Due donne da Campo
Due donne di Vau di Serchio
Una fanciulla da Sancto Lorenso
Uno gargione che portava la carne
Cieccarello del Piglio fratello di Piglio e col fratello Giovanni
Christofano lanberti tavernaio
Cieninno dela Spina tavernaio
Persavalli notaio del castello di castro e cierti autri
Homini e femine"
This is a lot of information to choose to leave out arbitrarily, so one can assume that the manuscript used by the RRIISS editor did not have this text to begin with. More important is what is contained in these twenty-four lines. The RRIISS includes a comment that in the British Library's manuscript immediately precedes the list of people describing how the "below written men (l'infrascritti homini) were lost following a storm on the 15th of June 1337. This would indicate that a list would follow, but does not, so we assume that this is an indication that it did not exist in the manuscript used by the RRIISS editors.
The list speaks of normal citizens of Pisa, including the little son of Cierino (lo filuolo di Cierino), someone who delivers meat (Uno gargione che portava la carne), and Persavalli, a notary of the castle of Castro (Persavalli notaio del castello di castro). It also includes a few women who are named with some level of specificity: Two women from Campo (Due donne da Campo), two women from Val di Serchio (Due donne di Vau di Serchio), and one maiden from Sancto Lorenso (Una fanciulla da Sancto Lorenso). As a group of average Pisans, their presence in the chronicle is remarkable, even moreso for the women of the list. This presence of non-elites, an underrepresented group in medieval history, in the text makes these lines an undeniably important portion of the chronicle. Their representation in the British Library's manuscript makes it an attractive alternative to the RRIISS version.
It also suggests a possible intended audience for the text. The chronicler does not often consider the human cost of the episodes recounted in the chronicle, and when he does here, it is not the important political figures that are mentioned, but instead the "everyman" Pisans who were killed. Why would the chronicler point to these people? Is it because he intended this work to be read by other people like this instead of people in power?