This appears to be used for handling TEMPORARY enchants to weapons - like POISONS. Also appears to be self-only.
hasMainHandEnchant, mainHandExpiration, mainHandCharges, mainHandEnchantID, hasOffHandEnchant, offHandExpiration, offHandCharges, offHandEnchantId = GetWeaponEnchantInfo();
hasMainHandEnchant = 1 (true) or nil mainHandExpiration = time remaining as thousandths of seconds mainHandCharges = charges remaining mainHandEnchantID = the spell ID of the main hand enchantment (new in 6.0) hasOffHandEnchant = 1 (true) or nil offHandExpiration = time remaining as thousandths of seconds offHandCharges = charges remaining offHandEnchantID = the spell ID of the off hand enchantment (new in 6.0)
Reference the default interface BuffFrame.Lua for its usage.