Today I clicked the link at the bottom of this page to validate XHTML via w3c and found out that my page’s content-type was being incorrectly reported. To trace down this error, I first looked through all the PHP for WordPress, found a few things in wp-functions.php and changed those to no avail. Then I remembered that WordPress stores most, if not all, of its configuration data in MySQL. Now the real work starts:

nep /srv/www/htdocs# grep “text/html” */* wp-admin/install.php:header( ‘Content-Type: text/html; charset=utf-8′ ); wp-admin/install.php: <meta http-equiv=”Content-Type” content=”text/html; charset=utf-8″ /> wp-admin/setup-config.php: header( ‘Content-Type: text/html; charset=utf-8′ ); wp-admin/setup-config.php:<meta http-equiv=”Content-Type” content=”text/html; charset=utf-8″ /> wp-includes/atomlib.php: $this->is_html = $attrs['type'] == ‘html’ || $attrs['type'] == ‘text/html’; wp-includes/class-phpmailer.php: $this->ContentType = “text/html”; wp-includes/class-phpmailer.php: $result .= sprintf(“Content-Type: %s;%s\ttype=\”text/html\”;%s\tboundary=\”%s\”%s”, wp-includes/class-phpmailer.php: “text/html”, “”); wp-includes/class-phpmailer.php: “text/html”, “”) . $this->LE; wp-includes/class-snoopy.php: // $rawheaders["Content-type"]=”text/html”; wp-includes/feed-atom.php: <link rel=”alternate” type=”text/html” href=”<?php bloginfo_rss(‘home’) ?>” /> wp-includes/feed-atom.php: <link rel=”alternate” type=”text/html” href=”<?php the_permalink_rss() ?>” /> wp-includes/feed-atom.php: <link rel=”replies” type=”text/html” href=”<?php the_permalink_rss() ?>#comments” thr:count=”<?php echo get_comments_number()?>”/> wp-includes/functions.php: ‘htm|html’ => ‘text/html’, wp-includes/functions.php: header( ‘Content-Type: text/html; charset=utf-8′ ); wp-includes/functions.php: <meta http-equiv=”Content-Type” content=”text/html; charset=utf-8″ /> wp-includes/functions.php: header( ‘Content-Type: text/html; charset=utf-8′ ); wp-includes/functions.php:<meta http-equiv=”Content-Type” content=”text/html; charset=utf-8″ /> wp-includes/general-template.php: if ( get_option(‘html_type’) == ‘text/html’ || $doctype == ‘xhtml’ ) wp-includes/general-template.php: if ( get_option(‘html_type’) != ‘text/html’ || $doctype == ‘xhtml’ ) wp-includes/pluggable.php: if ( $content_type == ‘text/html’ ) {