About us language file

Where is the language file in 7.1 that I can change the following text: "This site is powered by BoonEx Dolphin. The rest is a mystery." ? I do have a full license. I have found three 'about' language files and none contain this text. Any help is appreciated.

administration/lang_file.php
type in "This site is powered by" search and edit

tried that php file. . . and searched for the terms you mentioned. . . I couldnt find them. . . 

Please let me know if any alternative options is available. ..  

to change the text go into the language editor in admin.

Don't search for _about. Search for _ABOUT_US

ALL CAPITAL LETTERS. Exactly as i wrote it or it will not show up.

Or use my editor.

http://www.boonex.com/m/About_Us_Page_Editor