https://support.google.com/youtube/answer/71673 states:
The maximum file size you can upload is 256 GB or 12 hours, whichever is less. We've changed the limits on uploads in the past, so you may see older videos that are longer than 12 hours.
However, I saw this recent video https://www.youtube.com/watch?v=JgHRMd-sihk published 4 months ago, which is 24 hours 5 minutes and 28 seconds long. How can one upload a video of over 12 hours on YouTube?