Currently for VBR (variable bitrate) files, MB only displays the average bitrate of the VBR file being played (in the Track Information panel).
My suggestion is to display the average bitrate when not playing (as it currently does), and display the current bitrate when playing.
Its value would be updated 2-3 times per second to avoid flux.
The current bitrate would be displayed in the Track Information panel and status bar.
This would make it easier to realize that the currently played file is VBR, and also give a better sense of how the VBR encoding works in the current file,
as the quality of the sound drops significantly during portions of silence or simple sound and rises during more complex sounds to reduce the size of the file, while maintaining high quality.
It would be offered as an option to turn off if someone found it distracting.
For reference, I attach and two screenshots from MB's Track Information panel and status bar:


and a screenshot from foobar2000's status bar:

PS. Old related question post from 4 years ago:
live track bitrate visualization