It's when you have an elective so not rushed c-section and the do several things to make it mimic a vaginal birth slightly - A main benefit is to help ensure lungs are clear, delayed cord clamping, birth onto chest and check whilst mum is having skin to ski , apparently more common in the big London hospital. This link explains it better
https://newburydoula.co.uk/2013/08/20/the-natural-caesarean/