Using the latest Generic-Legacy nightlies, there are missing library dependencies for the music visualization plugins. Seems to be a case of the plugins being compiled for Generic (GBM) instead of Generic-Legacy (X11). Below is for shadertoy, but the others are similar.
I had cleaned out any archived copies in the packages folder, so I don't think it got a previously cached copies of the plugins.
Code
ldd: $warning: you do not have execution permission for `./visualization.shadertoy.so.20.3.0'
linux-vdso.so.1 => linux-vdso.so.1 (0x00007fff70fa6000)
libGLESv2.so.2 => not found
libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007ff15b05b000)
libm.so.6 => /usr/lib/libm.so.6 (0x00007ff15af7e000)
libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x00007ff15af5e000)
libc.so.6 => /usr/lib/libc.so.6 (0x00007ff15ad9e000)
/usr/lib64/ld-linux-x86-64.so.2 => /usr/lib64/ld-linux-x86-64.so.2 (0x00007ff15b2dc000)