I am not sure whether I remember this from college or somewhere else, but Jowett seems to have been considered a huge figure in classical greek studies. I see on Archive.org that he did a full set of translations of Plato's Dialogues prior to the Loeb Classical Library (translated by Fowler?) seeming to take over as the main source.
It appears from this bio that Jowett had an extremely active and interesting personal history, with lots of fairly "liberal" or 'reformist' opinions that he freely offered, so i bet we are going to find that most if not all of the commentary is his.
Benjamin Jowett - Wikipedia
en.wikipedia.org