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.
Conflicts: test/test_utils.py youtube_dl/__init__.py
That's what the help messages say. Previously it would only set '--skip-download', which would write thumbnail, descriptions or subtitles if they were requested (for example you may have set '--write-thumbnail' in the config file).