Openstreetmap: getting data of color #dddde8?

Larger pedestrian areas in OpenStreetMap usually use the highway=pedestrian tag or highway=footway + area=yes.

You can use Overpass API to query these features as long as the area is not too large:

[out:json][timeout:25];
(
  way["highway"="pedestrian"]({{bbox}});
  relation["highway"="pedestrian"]({{bbox}});


  way["highway"="footway"]["area"="yes"]({{bbox}});
  relation["highway"="footway"]["area"="yes"]({{bbox}});
);

out body;
>;
out skel qt;

You can view the result at overpass turbo, a web frontend for Overpass API. Also check the export button if want to download the data.