If you slam into another car, you’re liable for the damage to the other car.
Most car renters include liability insurance in their rates because if you weren’t able to pay, they could be held responsible (since they own the car). So they’re covering themselves as much as you.
Turkish rental agreements usually state that liability insurance is included “at the minimum amount required by law.” I suppose this means if things go really badly, you could be liable for some amount.
But let’s face it, usually we all just accept the amount offered (implicitly or explicitly) in the car rental contract as sufficient and let it go at that.
Far more important to consider is collision insurance and Tire, Glass and Headlight insurance (which-surprisingly–are not the same thing in Turkey).
Personal Accident/Injury protection is also offered by Turkish car rental companies.
Tire, Glass & Headlight Insurance