You have answered how it is possible, not why it happened: that is like someone pointing out that this "mysterious" commit is actually quite easy to explain, as a commit is an object in a git database, and we have all the metadata to see who made this one: I am extremely well aware of how it works (I give lectures at UCSB about git where I start by explaining the internal file formats and work my way up to the various command line tools), but I still found the question here of "why was this authored in February but only landed in November" fascinating, given the speculation about Oracle.