Here is the actual digital photograph of the uncial itself. The hash mark (to the left in the margin) is where the "Pericope Adulterae" actually begins in the text, and please note as a matter of passing interest that there are no marginalia or corrections by other editors. In other words, the copyist(s) for the Codex Bezae had written the uncial including the "Pericope Adulterae" as though it were actually an original aspect of the gospel narrative.
According to Holmes in his work, The Apostolic Fathers (Grand Rapids: Baker, 2007), the earliest documentation of the "Pericope Adulterae" are found from the Second Century AD. That is, in the 4th fragment of Papias (dated to the Second Century AD) there is the "Pericope Adulterae" almost cited verbatim as it would subsequently appear in Codex Bezae some 200-300 years later.
In other words, the oral tradition received by Papias and documented in his fragments in the Second Century are parallel to the "Pericope Adulterae" and documented in the Codex Bezae in the Fourth/Fifth Century. The problem is that the 4th fragment of Papias made no association of the "Pericope Adulterae" to the Fourth Gospel, or to any other gospel for that matter.
In summary, the Apostle Paul quotes the Lord Jesus (Acts 20:35) for which there is no gospel record, and which therefore shows that even the Apostle Paul had received an oral tradition to the effect that Jesus had once said, "It is better to give than to receive" (that is, Paul acknowledged to his listeners that he was aware that Jesus had once stated that phrase during his earthly ministry). In that vein, the "Pericope Adulterae" appears to have been another such oral tradition among Christians that first appeared in writing by Papias in the Second Century. Later, copyists in the Fourth/Fifth century (Codex Bezae), and of course others later, have tried to shoehorn this "orphan" account from oral tradition into various places within the Fourth Gospel (but with a preponderance of preference at John 7:53-8:11). Why the gospel of John? Holmes cites in The Apostolic Fathers that Papias was associated with those who had been associated with the Apostle John (Polycarp, et al.), and thus the inference to the Apostle John.