\Q and \E don't work inside interpolations. They only work in regexp literals

Fascinating theory, but easily proven wrong:

print "\Qabc*def­\E\n"; # prints abc\*def
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Your example shows a \Q being used inside of a quoted string, not inside of a string value being interpolated (into a string or regex). You've misunderstood how "interpolation" was originally used.

I'll agree that the original use of "interpolation" wasn't clear enough. Though, double-quoted strings allow interpolation but I wouldn't call a quoted string that didn't contain any variables "an intepolation".