It's commonly referred to as the "steering accumulator" ... which it isn't, it's a second brake accumulator required only on the early imported CX's due to the insane diagonal braking system forced upon us by the standards of the time.

It is critical you keep the two brake accumulators gas'd. If they ever get flat enough, the sphere membrane will rupture against the filler plug instantly filling the braking system with nitrogen (don't ask me how I know this !!).

All it means in reality is you have an extra sphere to upkeep for no good reason.

seeya,
Shane L.