I'm using the Cinnamon
desktop environment (on Debian Sid), whose window manager has no option to, let's say so, undecorate an application window.
As I see that a number of programs manage to tell the above window manager that they will provide frames and whatsnot on their own (e.g., google chrome), I wonder if it exists, or can be written, a wrapper to be called like this
$ noframes mupdf my16:9slides.pdf
that starts, tell the window manager not to worry about frames etc, starts my application and reparents it.
The (maybe marginal) benefit is that the window aspect ratio, in my example, will be more approximately equal to 16:9 and the window will fit almost exactly the available space when using the zoom to 1/4 screen feature.
PS: from my .twmrc
NoTitle {"mupdf" ...}