Does a land that produces mana of any color count as every color for color identity in Commander?

In Commander, a card's color identity is determined by the color of every mana symbol appearing in its mana cost and rules text, plus any color indicators or characteristic-defining abilities (CR 903.4). The phrase 'mana of any color' does not itself contain specific colored mana symbols (W, U, B, R, G), so it does not add all five colors to the card's identity.

A land like Glimmervoid has the text 'Add one mana of any color' but contains no colored mana symbols in its rules text. Therefore its color identity is colorless, and it can be included in any Commander deck regardless of the commander's colors (CR 903.4, 903.5b).

Contrast this with a card like Command Tower, which also says 'Add one mana of any color in your commander's color identity' — it too has a colorless color identity. Meanwhile, a land like Breeding Pool has the symbols {G} and {U} in its type line or rules text, giving it a green and blue color identity.

Concrete example: Suppose your commander is mono-white (Heliod, God of the Sun). You want to include Glimmervoid in your deck. Since Glimmervoid has a colorless color identity (no colored mana symbols appear in its text), it is legal in the deck, even though it can technically produce red or black mana during a game.

The rules care about what symbols are printed on the card, not the runtime flexibility of what mana it can generate. This is clearly defined in CR 903.4 and supported by CR 202.2, which specifies how color identity is derived from mana symbols in rules text.