When you add files to the <head> via response.files.append, web2py check if its a .css or .js and creates the html <link> according:
css: <link href="path/file.css" rel="stylesheet" type="text/css" /> js: <script src="path/file.js" type="text/javascript"></script> But if you want to change the rel attribute how can you do it? We need it because of LESS http://lesscss.org/#-client-side-usage that has an rel="stylesheet/less"
