I wonder if it could be something which you have unplugged and no longer use, like a USB drive for example.
I have to admit that my inate sense of cowardice would come to the fore in this case. If it's working as it should, then leave well alone!!
OnePlus 5T review: Hands-on
Illustrator Andrés Lozano on his improv line work, brazen use of colours & hand sketching
iPhone X review
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