No, I'm not calling this a "potential biosignature" ๐
Mars Guy has documented some of the rover team's prior work on coated rocks, although I don't remember seeing any examples this visually striking.
The coated rocks which have been documented prior to this one - none of which were nearly so patchy as this one, if I recall correctly - have been interpreted as a relatively thick dust coating formed by the action of water vapor, i.e. humidity. Mars should have had some fairly recent episodes of higher atmospheric moisture caused by the tilting of Mars' axis, which would expose the polar caps to more sunlight and temporarily humidify the atmosphere while the ice is being redistributed to the new polar latitudes.
We've never had any mission climb the rim of a crater as large as Jezero before... not on Mars, or even on Luna... I'd say it's been pretty fun so far!
Hopefully we'll see more funding on Earth to research on similar coatings that occur here on Earth