Comment 54 for bug 71593

Well python-opengl and python-gtkglext1 are not "dependences" because they are optional.
They are only needed for 3D, so they're not dependencies.
Chess should prompt to install them upon user try switch to 3D mode.

Chess is no longer installed by default?
What is this?
Chess is the most popular and successful game ever in history!
Ubuntu must have chess! Windows have it!