Mass Effect & Mass Effect 2
Despite all the evidence confirming the existence of the Protheans, little is known about their culture and society. From time to time, dig sites will yield new clues, but after 50,000 years of decay, little of value is unearthed.
Recent research has focused on the discovery of Prothean data discs. On their own, they are frail and rarely found in one piece. Occasionally, however, an intact disc will be discovered within a console or reading device.
To date, over three dozen discs have been recovered and a few of those have been restored to the point where researches can begin analyzing them. Though it may be some time before scientists discover a way to transfer the data off the discs, they are currently considered the most tangible leads for learning more about the Prothean culture.