Are extra effects considered weapon damage on a sword of sharpness?

The Sword of Sharpness says:

When you attack an object with this magic sword and hit, maximize your weapon damage dice against the target.

Do some other effects (language use is intentional) add on to this, or is it only the weapon’s damage based on the weapon chart in the Player’s Handbook?

Examples:

  • Are the rogue’s Sneak Attack damage dice maximized?
  • Is the Bugbear’s extra damage die from its Brute trait maximized?
  • If I customize the sword to do extra cold or fire damage (based on a die roll), are those damage dice maximized?