If a device is connected you get a green dot. If the device is not connected you get a red dot.
Be aware that there is something as Deuteranopia (red-green color blindness). Not everyone can distinguish these colors very easy. So maybe make an extra indication (for example by the word active, in case device is connected).
Same remark for feature explorer, where different colors are used. I don’t find any color configuration settings so maybe a nice (future) feature will be a color blind friendly dashboard. This will improve the user experience.