Does “explicit” keyword have any effect on a default constructor?

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Reading explanation of members :

explicit char_separator(const Char* dropped_delims,
                        const Char* kept_delims = "",
                        empty_token_policy empty_tokens = drop_empty_tokens)
explicit char_separator()

The explicit keyword for the 1st constructor requires explicit creation of objects of char_separator type.
What does the explicit keyword mean in C++? covers the explicit keyword very well.

The explicit keyword for the 2nd constructor is a noise and is ignored.

EDIT

From the c++ standard :

7.1.2 p6 tells :

The explicit specifier shall be used only in declarations of
constructors within a class declaration; see 12.3.1.

12.3.1 p2 tells :

An explicit constructor constructs objects just like non-explicit
constructors, but does so only where direct-initialization syntax
(8.5) or where casts (5.2.9, 5.4) are explicitly used. A default
constructor may be an explicit constructor; such a constructor will be
used to perform default-initialization or value-initialization (8.5).
[Example:

class Z {
public:
explicit Z();
explicit Z(int);
// ...
};
Z a;               // OK: default-initialization performed
Z a1 = 1;          // error: no implicit conversion
Z a3 = Z(1);       // OK: direct initialization syntax used
Z a2(1);           // OK: direct initialization syntax used
Z* p = new Z(1);   // OK: direct initialization syntax used
Z a4 = (Z)1;       // OK: explicit cast used
Z a5 = static_cast<Z>(1); // OK: explicit cast used

—end example]

So, the default constructor with the explicit keyword is the same as without this keyword.

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