API C ArtifactUI.GetArtifactInfo

Returns information about the currently equipped artifact weapon. itemID, altItemID, name, iconFileDataID, powerAvailable, ranksPurchased, quality, artifactAppearanceID, appearanceModID, itemAppearanceID, altItemAppearanceID, altOnTop = C_ArtifactUI.GetArtifactInfo

• Values 3 and 11 only apply to artifacts that provide both a main-hand and an off-hand item (such as Felo'melorn). Artifacts that are two-handed (with the exception of Odyn's Fury and Helya's Wrath) will return these values as 'nil'.
• Values 10 and 11 will return 'nil' if no transmog has been applied to their corresponding items.
• Values 3 through 7 are not explicitly named anywhere in Blizzard's API; their names are assumed based on their function