When browsing project templates in Apple’s iMovie (File > New Project), the app injects your name into some template previews, before you ever pick one and get to work. In my example, I’m previewing the “Road Trip” movie trailer template, and iMovie added my name to the end credits in a bunch of places, including as “a David Chartier film.”
I presume it’s grabbing the current user’s name either from the Users & Groups System Preferences pane or the “me card” in Contacts, assuming the user has set one.