Pega Robotics supports Internet Explorer, Chrome, and Firefox but it does not support explicit websites. There is no explicit support for the Appian BPM web app. That does not mean it will not work but that means Pega Support cannot assist you if you encounter issues with the webpage.
I don't understand the question. Can you repeat it in a different way?
The Support Matrix is the correct place to check if the web app is supported. If it is not there, then it is not supported.
Keep in mind though, that "not supported" does not mean "it won't work". It just means, we do not manage or test against a particular technology, framework, or application so we do not guarantee that methods will work with the application.