What data fields are available to me at receipt template
In the message template, put this in the &lt;body&gt; section of the html format section and then send yourself a contribution receipt.

{assign_debug_info}
&lt;table id="table_assigned_vars"&gt;
    {section name=vars loop=$_debug_keys}
        &lt;tr class="{cycle values="odd,even"}"&gt;
            &lt;th&gt;{ldelim}${$_debug_keys[vars]|escape:'html'}{rdelim}&lt;/th&gt;
            &lt;td&gt;{$_debug_vals[vars]|@debug_print_var}&lt;/td&gt;&lt;/tr&gt;
    {/section}
&lt;/table&gt;


This does basically the same thing as using {debug} in regular smarty templates to see the variables in the UI.