What is the “Other” that is showing up in Geo Reporting?

This article discusses why "Other" is showing up in the geo section for reporting

Sometimes an ‘Other’ category populates in the geography section of the campaign in the ui.marketing reporting dashboard. This can sometimes populate in geo reporting because if too many geographic rows are returned for that geo component, we will collapse all the additional rows into one single component in the reporting.

We only show geo reporting on the top 1,000 locations, and these are sorted by impression delivery.