Adding these two YMLs will create collections for a seven continent configuration (as opposed to the six UN regions used by the default continent.yml) and a version of the countries.yml which groups countries with low output that are culturally similar - such as 'Balkans', 'Nordic', 'Middle East' and 'Pacific Island'.
The entry overlay file adds a country flag defined by the audio language of the entry to the top right corner. So Mayan gets a Mexican flag, and English gets an English flag for instance. This is inexact, as languages are not countries. Spanish is great for films from Spain; but a Portuguese flag on a Brazilean film could be confusing. Furthermore, many films have an unknown or multiple audio languages - this needs to be fixed at the file levelv however with a tool such as mkvtoolnix.
The overlay yml adds a country flag defined by the audio language of the entry to the top right corner. Note that languages are not countries. Portuguese is great for films from Portugal; but its flag on a Brazilian film could be confusing. Furthermore, many films have an unknown audio language in Plex - this requires fixing at the file level with a tool such as mkvtoolnix.