Those are aftermarket ignition wires, the factory wires are all black. Due to how hot the engine compartment and the spark plugs get, the ignition wiring boot can be very tough to remove from the spark plug. After years of struggling with that, I finally bought a spark plug boot removal tool which is like an angled set of pliers and it makes that part of the job much easier.
If you end up destroying/pulling apart your ignition wires changing your plugs, which is common with many poorly constructed aftermarket ignition wires, I would replace them with the OE wires from the dealer. Many aftermarket parts are highly desirable but on things like the ignition wires, sensors, water pumps, starter motors, etc., I always strongly recommend the OE parts from the dealer due to their generally superior quality and longevity. Especially on the ignition wires since too many aftermarket ignition wire sets just cause problems like with radio static or they are so shoddily made they pull apart the next time you go to remove them.