Tinkering with "Powered By" with poor knowledge

[FuzMic]

Hi gurus

In a web page we may have some "Powered By" plus blablabla coming from using some extensions. Their size & wordings may not suit the overall design of things and we want to tinker with it.

Using firebug we identify how the wording comes about because of my lack of web tools knowledge has to dig all over the sub Admin folder in a Joomla site to find it. So if guru can teach me how to use firebug to pin point it's location fast, it will be great to train my learning curve.


The real question is how this:
With the little knowledge i know, there is constraints in changing the string

1st case (can change)
$version ='<a style="display: inline; visibility: visible; font-size: 10px; text-decoration: none;">Powered by Access</a>';
being use in
$body = preg_replace($regexp, "$0&nbsp;&nbsp;" . $version, $body);



HOWEVER this is not possible in some case especially when it involves a function
2nd case (CANNOT change)
function putLine()
{
$put_text = JText::_("PUTLINE_TEXT");
$html = "<div style=\"text-align:center; font-size: 10px;\">" .
htmlspecialchars($put_text) .
"&nbsp;Powered By <a href=\"http://www.access.com\">Access Corp/a></div>";
return $putLine;

being use in
if(!$mainframe->isAdmin() && $encryptConfig->get('showbacklink', 1))
$body = str_replace("</body>", $this->putLine() . "</body>", $body);
}
JResponse::setBody($body);
}


The missing knowledge in my learning curve is:
In the 2nd case, whatever i change it will not appear in the web page. In firebug if i make changes on it, it will appear in the web page for that moment.

This lack of knowledge really bugs me and to fill this void is no longer easy in this complex word. Teach me please, thanks first.