Now they use an XML format instead of JSON.
We have the minsize test now.
These fluctuate regularly.
For playlists, YoutubeDL would set it to the playlist url.
At least with avconv 11, it will print 'avconv version 11, ..' to stderr, not stdout.
This embed style is used on http://www.bitburger-open.de/ , but that is not included as a test case since the format is likely to be temporary.