At the risk to sound like a paranoid tinfoil hat wearer, What are the other things?
You mean like this?:
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But seriously... You probably have seen those as well. They are also glued (with one really tough glue) to the inside of the case, about 5mm wide, 40mm long and 2-3mm high.
Nothing to be paranoid about, it's not to locate your home but only for use in shops, so that the alarm would ring if you leave without paying.