The text "Day Scheduling View" is stored in a Custom Label, and this text can be changed / overridden by doing the following:
1. Enable Translation Workbench --- go to Setup > Translation Settings, and enable Translation Workbench. You may have to add yourself as a translator for English. 2. Go to Setup > Custom Labels, and go to the "D" page to find the Custom Label "Day Scheduling View". You should see a related list called "Local Translations / Overrides". Click "New Local Translation / Override". Set Language to "English" and Translated Text to "Day View". Click Save.