Hi Shu
_satellite.pageBottom() is the footer code for DTM. DTM is Adobe's Tag Management System, so this code is the second half of the tag container (there should also be header code at the top of the page).
Adobe Analytics is then fired from within DTM.
Browser and OS are out of the box reports, and don't require any custom implementation to make them run. They are derived from the User Agent string which you can see in the network tab of developer tools in your browser.
What metrics are you using in the Browser Report/ OS report? They could impact whether you see a 'None' value.