You are sharing a map that contains a KML layer as a web map. The <value> parameter refers to the unzipped size of the KML layer that is larger than the 10 MB limit. Although the map viewer is unable to display KML layers that are larger than 10 MB, the web map can be opened and displayed successfully in ArcGIS Pro.
Solutions
- Do nothing. The web map will share successfully and can be viewed in ArcGIS Pro without issue. When attempting to view the web map in the map viewer, the KML layer will not be added.
- Remove the KML layer from the map before sharing.
- Re-create the KML layer with fewer features or attributes.
More information
For more information on what functionality is supported and what limitations exist with KML layers in the map viewer, see: What is KML?.