There is a mysterious port on the Apple Watch that could be used to connect accessories such as a smart band or battery, reports TechCrunch. The outlet says that multiple sources have confirmed the wearable features a secret 6-dot brass contact used for diagnostics and direct access to the operating system.
Apparently the port is very similar to the Lightning port found on larger iOS devices, and is located inside the groove of the "bottom" strap connector slot. It's believed that this portal is "absolutely necessary" to install the Watch OS during manufacturing, and thus it will be present on shipping versions of the wearable.