UI continues working even if favourite route is no longer available
Line search does not work any more
Add a favourite route, say line 550.
In devtools, check the localstorage and modify the GTFS id to a value which does not exist in data.
Try seaching any line, say M1, 4 or 550. Search does not find any lines at all.
If user adds a favourite route which later is removed from data, line search stops working. Non-existent favourite is no longer visible in UI and cannot be removed.