libosmesa6 21.0.3-0ubuntu0.3~20.04.1 (armhf binary) in ubuntu focal

 OSmesa is a Mesa extension that allows programs to render to an
 off-screen buffer using the OpenGL API without having to create a
 rendering context on an X Server. It uses a pure software renderer.
 .
 This package provides both 16-bit and 32-bit versions of the off-screen
 renderer which do not require external libraries to work.