What does Ma10p stand for? i.e. a file is listed as being "1920x1080 HEVC Ma10p FLAC"

So....resolution / h.265 video codec / ? / .flac audio codec

On its own I'd guess the 10 stands for 10 bit depth, but the Ma is unknown to me. Other guesses is its some kind of h.265 preset.
"Main 10" stands for 4:2:0 10-bit color, and I'm Pretty sure "Ma10p" is just another way of saying Main 10.