HTML5 is by default the web browser tabs have as title or header "HTML5" written.

You can change what is displayed this way:

Open the settings.js file 

located in 

C:\Program Files (x86)\TSplus\Clients\www\software\html5\

And change the HTML5 value for what you want in this line:

W.setDocuTitle = function() { try { document.title = "HTML5"; } catch(b) { } }();

Save the file.

And make sure you restart the TSplus web server to apply the change!