user35865: The video converter incorporated in VLC warns me when I select the MKV format with the message: This muxer is not provided by VLC. It could be missing.
Is there an official list of these MKV-related packages?

I'm using VLC 3.0.9.2 in an Ubuntu based distro.

user35763: It is not an issue. VLC has many built-in codecs. MKV is not in them. So VLC rely on libmatroska to manipulate MKV. As VLC cannot know if you have it installed, it gives a warning. Check if libmatroska is installed or not, using dpkg or apt.

35865: <p>The video converter incorporated in VLC warns me when I select the MKV format with the message: <code>This muxer is not provided by VLC. It could be missing.</code></p>
<p>Is there an official list of these MKV-related packages?</p>
<p><a href="https://i.stack.imgur.com/BBQHA.png?s=256" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/BBQHA.png?s=256" alt="mp4 screenshot" /></a><a href="https://i.stack.imgur.com/uvuZN.png?s=256" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/uvuZN.png?s=256" alt="mkv screenshot" /></a></p>
<p>I'm using VLC 3.0.9.2 in an Ubuntu based distro.</p>
 35763: <p>It is not an issue. VLC has many built-in codecs. MKV is not in them. So VLC rely on <code>libmatroska</code> to manipulate MKV. As VLC cannot know if you have it installed, it gives a warning. Check if libmatroska is installed or not, using dpkg or apt.</p>
