libosmesa6 21.2.6-0ubuntu0.1~20.04.2 (i386 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.