Is Mirror of the Forebears legal in Standard, Modern, and Commander?

Mirror of the Forebears is legal in: Legacy, Vintage, Commander.

What type of card is Mirror of the Forebears?

Mirror of the Forebears is an Artifact. Its oracle text reads: "As this artifact enters, choose a creature type. {1}: Until end of turn, this artifact becomes a copy of target creature you control of the chosen type, except it's an artifact in addition to its other types."

Mirror of the Forebears

Artifact

As this artifact enters, choose a creature type.

: Until end of turn, this artifact becomes a copy of target creature you control of the chosen type, except it's an artifact in addition to its other types.