Why OpenCV use YCrCb instead of YCbCr for color space conversion?

Say, I would like to convert an BGR image to YUV or YCbCr space. The function is cv::cvtColor.
What makes confuse is that, there is cv::COLOR_BGR2YUV, cv::COLOR_BGR2YCrCb, but there is’t the expected cv::COLOR_BGR2YCbCr.

What is the purpose that using YCrCb, instead of the more often mentioned YCbCr, i.e. the counterpart of YUV?

might just be a typo and nobody noticed until now. or it might be a real bug, which is possible.

feel free to submit an issue on the github and maybe investigate if the code does the right thing or not.