html - tpl ファイルの "{# ... #}" タグの意味は何ですか?

Question

以下のコードのすべての {# ... #} タグの意味は何ですか?

 {include file="header.tpl" title="install" showheader="no"}

<div class="install" style="text-align:center;padding:5% 0 0 0;">
    <div style="text-align:left;width:500px;margin:0 auto;padding:25px 25px 15px 25px;background:white;border:1px solid;">

        <h1>{#installcollabtive#}</h1>

        <div style="padding:16px 0 16px 0;">
            <h2>{#installstep#} 3</h2>
            <em>{#createadmin#}</em><br /><br />

            <form class = "main" name = "adminuser" method = "post" enctype="multipart/form-data" action = "install.php?action=step3">
                <fieldset>
                    <div class = "row"><label for = "username">{#name#}:</label><input type = "text" name = "name" id = "username" /></div>
                    <div class = "row"><label for = "pass">{#password#}:</label><input type = "password" name = "pass" id = "pass" /></div>
                </fieldset>
                <br />
                    <div class="row-butn-bottom">
                        <label>&nbsp;</label>
                        <button type="submit"  onfocus="this.blur();">{#continue#}</button>
                    </div>
                </fieldset>
            </form>

                </div>
            </div>
        </div> {*Install end*}
    </body>
</html>

どんな助けでも大歓迎です、どうもありがとうございました!