Many thanks for your analysis. You have pinpointed many of the risks that I overlooked in my tests.
I didn't think about a string ending with a backslash. I will follow your suggestion about doubling the quotes. It is unlikely to happen that much, though. Having three different quotes available, the users should be able to use the more appropriate symbol to avoid clashes.
"\t" was just a test, it wasn't supposed to be extended (at least in this script.)

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