Alien Anomalies

I have found a Microscopic Imager image which shows some blacking out and I cannot see what it is they are blacking out.

I can see pieces of it at either end of the black part and pieces of what looks like pipe or root or something extending further off at each end into the 'blueberries'.

Does anyone have any ideas what this could be please - see the link at the top?

The area in question is top left area of the image and running in a sort of line bottom left to top right. This is on the edge of where the Rover has pressed down on the ground with its RAT Rock Abrasion Tool.