Filter list should correspond to the buttons at the top of the dialog. You can filter what shows up on the right side, filtering by either the package name, by which library you selected on the left side or showing all of them.Because you have component 49 selected and it’s a resistor, it’s trying to match with 0603, 1206 , etc
As for the stuff from github, there is a wizard you can reach from the layout editor that guides you through either syncing with the github libraries or pulling them local and working from there.