One more detection is related to the missing subdomain - http://manual.erpnext.com
It now redirects to the sign-up form (https://erpnext.com/signup?plan=Free&domain=manual.erpnext.com), whatever URL within this subdomain is specified. In turn, some earlier forum posts as of 2015 referred pages on manual.erpnext.com (see Customize forms and Link type woes. Can anybody lend a quick minute to help? - #2 by saurabh6790, for instance - it refers to Frappe Cloud ).
It would be better if manual.erpnext.com redirects to the appropriate location of developer manuals as of the end of 2016.