A fork of gnome-shell-extension-mpris-indicator-button by JasonLG1979 . Tooltip removed, and its content put into the label, for memorable screenshots.
The label can grow indefinitely unless you put some code to trim it. Gnome-shell trims it for me anyway, when it extends till the centered elements of the panel, so I'm fine as is.
Copied from this version on 28 August 2021. Made just a trivial change without even knowing javascript: every credit goes to the authors as described in the original README. I won't reliably update this version as I made the change for myself, on Debian stable (gnome-shell 3.38).