Example of Proper Usage:

'Andreessen Horowitz' → 'YouTube URL' → 'https://www.youtube.com/channel/UC9cn0TuPq4dnbTY-CBsm8XA' is correct, is this URL is the primary and official YouTube channel associated with a16z.
'Magnus Carlsen' → 'YouTube URL' → 'https://www.youtube.com/c/themagnuscarlsen/featured' is correct, as this URL is the primary and official YouTube channel associated with Magnus Carlesen. https://www.youtube.com/c/themagnuscarlsen/about helps confirm this is his official channel.

Example of Improper Usage:

'Magnus Carlsen' → 'YouTube URL' → 'https://www.youtube.com/watch?v=mVzOdnGz2WM' is incorrect, as this URL is a YouTube video posted by Magnus Carlesen's account, but not the primary and official YouTube profile URL associated with Magnus Carlsen.
'Croatia' → 'YouTube URL' → 'https://www.youtube.com/c/RoyalCroatianTours is incorrect, as this URL is not the primary and official URL associated with the country of Croatia, but rather a URL associated with one of Croatia's tourism groups.