is-preview

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1. WordPress Plugin Displays the Type of Document, is_page, is_single …

   … is_feed, is_home, is_month, is_page, is_plugin_page, is_preview, is_robots, is_search, is_single, is_singular, is_time, is_trackback, is_year, is_404. … wordpress/what-is-this-plugin.html

2. SEO Boost from 404 Plugin? Focus on humans

   … is_404() || is_trackback() || is_search() || is_comments_popup() || is_admin() || $is_IIS || ( isset($_POST) && count($_POST) ) || is_preview() ) … seo/404-google-wordpress-plugin.html