Black chainstay: this part was cracked and then replaced by the shop where I bought the bike. The replacement was done by a professional; the only difference is aesthetic (black instead of blue), the structure is sound.
Typical signs of wear from mountain bike use: scratches and paint chips in some places (bottom of the down tube, chainstay/seatstay, contact areas). Nothing structural, only cosmetic.

The bike rides perfectly. I can provide additional photos of any area upon request.