You might know that Piwik was renamed into Matomo more than a year ago. While everything is still compatible and even the scripts and other (internal) data is still named piwik, the rename is affecting more and more areas. Upstream is working hard to finalize their rename - while trying not to break too much on the other side. But even the file names will be renamed in some future version.
Time - for us - to do some maintenance and start following upstream with the rename. Luckily, our famous distribution already has matomo packages in the main repository (which currently still miss Apparmor profiles, but hey: we can and will help here). So the main thing left (to do) is a database migration and the adjustments of all the small bits and bytes here and there, where we still use the old name.
While the database migration silently happened already, the other, "small" adjustments will take some time - especially as we need to find all the places that need to get adjusted and also need to identify the contact persons, who can do the final change. But we are on it - way before Matomo upstream will do the final switch. :-)