Symbolism, Imagery, Allegory
Perhaps because Franklin's a printer by profession, examples from that trade are sprinkled throughout the Autobiography. The most notable of these is "errata," which is printer-speak for errors. See, before word-processing and computers, people used printing machines that were a lot more like typewriters. If you've ever used a machine like that, you know that you can't erase a mistake once you make one: you're left with a permanent error.
Franklin uses this word to talk about the mistakes he makes; whenever he wants to say he screwed up or did something badly, he frames it as one of his "errata." We get the sense that these mistakes have really left marks on him, and that they've left almost tangible impressions on his character. His word usage also calls attention to his dual role as both author of the Autobiography and its subject, since it reminds us of the physical and technical elements of writing and publishing a book, while also underscoring the profession of its main character.