Just a test with all variations of brackets, parentheses, and & forms: 

[​] [​] [​] (​) (​
+) (​)

[download]

Preview shows exactly the same as shown in the <code> block above. Now let's see what happens when I post this.

Update after posting: What I saw in Preview is exactly the same as I now see in the individual node, the entire thread, Newest Nodes, and RAT.

Update after looking more closely: Sorry, what I said in the last update about the "the entire thread" is incorrect. When I look at the whole thread, all the various & references are resolved; giving this title: 

Re^3: What are the formatting rules for the "Title" of posts? [&#8203;
+] [&#8203;] [&#8203;] (&#8203;) (&#8203;) (&#8203;)

[download]

— Ken

In reply to Re^3: What are the formatting rules for the "Title" of posts? [&#38;#8203;] [&#x26;#8203;] [&amp;#8203;] (&#38;#8203;) (&#x26;#8203;) (&amp;#8203;) by kcott
in thread What are the formatting rules for the "Title" of posts? by kcott

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
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  • See Writeup Formatting Tips and other pages linked from there for more info.