Google-maps – What do the different colors mean in Google timeline

These are city and sub-locality boundaries that are displayed when you search for a specific locality.

• googlesystem.blogspot.com - Unofficial Description of this change.

The green areas are defined clickable regions on the map. In the United States and Canada, they are closely aligned to state and province borders. In other parts of the world they follow country borders. When I click on one of the green regions, the map shows a list of participating transit providers in that particular region.

The regions are polygons defined in the file http://www.google.com/intl/en/landing/transit/js/transit.data.js

The code that draws the map is in the file http://www.google.com/intl/en/landing/transit/js/transit.map.js

Note that the green polygons will not show in Internet Explorer. From transit.map.js:

// Don't display polygons for IE as they are taking too long to load.
if (!new tmap.utils.Browser().msie) {
  this.map.addOverlay(obj.polygon);
}