nor does it free the SVs that form its elements

moron is partially correct, it does free the SV's that form its elements. Although indirectly via refcount decrement. Thats what the follow code does:

while (index) {
    SV * const sv = ary[--index];
    /* undef the slot before freeing the value, because a
     * destructor might try to modify this array */
    ary[index] = &PL_sv_undef;
    SvREFCNT_dec(sv);
}
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