conutry_codes_with_flag is a github repository to store all the data of all countries and with their flags, there could be multiple uses of this data.
Follow this link to get json data https://raw.githubusercontent.com/fullstackrajkumar/country_codes_with_flag/main/country_codes_with_flag.json
Save the data as country_codes.json file, and use it. and you could use as cdn also