Except... they were correct. Google has now clarified that they're removing the code behind the undocumented items, with noindex called out explicitly. https:

Except... they were correct. Google has now clarified that they're removing the code behind the undocumented items, with noindex called out explicitly. https://webmasters.googleblog.com/2019/07/a-note-on-unsupported-rules-in-robotstxt.html https://webmasters.googleblog.com/2019/07/a-note-on-unsuppor... It wasn't officially supported / the recommended way - but it worked (in many cases.)