Added wiki and youtube guide link as placeholders. Add to recently opened in home screen after publishing. Show PUB badge. Add .published as a file save name hint.

src/slic3r/GUI/MainFrame.hpp

@@ -179,6 +179,7 @@ class MainFrame : public DPIFrame
     {
         FileHistory(int max) : wxFileHistory(max) {}
         std::wstring GetThumbnailUrl(int index) const;
+        bool        GetPublished(int index) const;
 
         virtual void AddFileToHistory(const wxString &file);
         virtual void RemoveFileFromHistory(size_t i);
@@ -189,6 +190,7 @@ class MainFrame : public DPIFrame
         void SetMaxFiles(int max);
     private:
         std::deque<std::string> m_thumbnails;
+        std::deque<bool>        m_published_files; // parallel to m_thumbnails: is it a published 3mf?
         bool m_load_called = false;
     };