This task is a placeholder for @MMiller_WMF and @RHo to revise the copy for variant tests C & D.
This will include:

• Providing final copy for new content - e.g., the "Welcome" message on the homepage.
• Updating existing copy - e.g., shortening the personalized text that shows above topics selection in variant D; text for the topic selection in variant D revised to let users know that topic selections can be changed.