The is a 360p AVC video stream. While it's rarely the "best" quality available, it is one of the most reliable and compatible formats in YouTube's massive library.
If you are a developer or a power user who wants to specifically target this format for data saving or testing, you can use the yt-dlp command-line tool : 230 mp4
[YouTube] Unable to reliably report file formats 136 and 140 #13962 The is a 360p AVC video stream
yt-dlp -f 230 [URL] Note: This will download video only. To get audio as well, you would use -f 230+140 . Is 360p Still Relevant? To get audio as well, you would use -f 230+140
Below is a draft for a technical blog post explaining what this format is and how to use it. Understanding the 230 MP4 Format: A Guide to YouTube itags
While we live in an era of 4K and 8K, the 230 MP4 format remains a cornerstone for: