In answer to number 1, the space is still there. You can easily confirm your theory by adding a line like:

print "-\n";
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after you print the list. The space should be quite obvious then.

As for your second question, remember: "concatenates all the elements of LIST together and then returns the reverse of that, character by character." So first your list becomes "firstsecondthird" (a short version of it), then that is reversed to "driht...".