No, it's a worldwide thing. It's not just a muffler which has an earthing strap. Have a good poke around underneath any modern vehicle and you will probably find 4 or 5 of them lurking around. They simply help equalise any build-up of charge. This prevents static (reducing the likelihood of spiking sensitive electronics), and also helps reduce the likelihood of galvanic corrosion in some components (like mufflers for example - if you ever saw how much water collected in mufflers in cold-climate vehicles it might give you an idea).

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Cheers,

Anthony