By default Web Tracks and Video Tracks are now implemented by Chromium Browser and VLC respectively. The old implementations of UZBL and omxplayer are still available but may be removed in the future.
Chromium browser is the modern browser which is the standard for RPi OS. It handles heavy Javascript and video much better than UZBL which has not been updated since 2016.
VLC is now the standard Videoplayer for RPi OS. Omxplayer has been deprecated and is not being developed further because the underlying omx API is also deprecated.
You will need to update profiles and install new dependencies to use the new version so read the Readme, Release notes, Changelog, and Manual.
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