Are you saying the documentation is wrong? And not once but twice: You can also use special names to select particular edge case format: * best:

Are you saying the documentation is wrong? And not once but twice: You can also use special names to select particular edge case format: * best: Select best quality format represented by single file with video and audio And again: > Since the end of April 2015 and version 2015.04.26 youtube-dl uses -f bestvideo+bestaudio/best as default format selection (see #5447, #5456). If ffmpeg or avconv are installed this results in downloading bestvideo and bestaudio separately and muxing them together into a single file giving the best overall quality available. Otherwise it falls back to best and results in downloading the best available quality served as a single file