Does anyone know what the purpose of the base64 encoded strings are in the asset URLs? e.g. If we extract a chunk out of: https://world.hey.com/dhh/a44bf3f3/

Does anyone know what the purpose of the base64 encoded strings are in the asset URLs? e.g. If we extract a chunk out of: https://world.hey.com/dhh/a44bf3f3/representations/eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaHBCS3pPcFJVPSIsImV4cCI6bnVsbCwicHVyIjoiYmxvYl9pZCJ9fQ==--d6e0347adccef036865079d910ade9601dd527d5/eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaDdDam9MWm05eWJXRjBTU0lJYW5CbkJqb0dSVlE2RkhKbGMybDZaVjkwYjE5c2FXMXBkRnNIYVFLQUIya0NBQVU2REhGMVlXeHBkSGxwU3pvTGJHOWhaR1Z5ZXdZNkNYQmhaMlV3T2cxamIyRnNaWE5qWlZRPSIsImV4cCI6bnVsbCwicHVyIjoidmFyaWF0aW9uIn19--e2b7e3d9ad63061a4461ddc0db7057b9f1ddfa3e/whats-a-computer-ad-from-apple.jpg https://world.hey.com/dhh/a44bf3f3/representations/eyJfcmFpb... We get this string: eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaDdDam9MWm05eWJXRjBTU0lJYW5CbkJqb0dSVlE2RkhKbGMybDZaVjkwYjE5c2FXMXBkRnNIYVFLQUIya0NBQVU2REhGMVlXeHBkSGxwU3pvTGJHOWhaR1Z5ZXdZNkNYQmhaMlV3T2cxamIyRnNaWE5qWlZRPSIsImV4cCI6bnVsbCwicHVyIjoidmFyaWF0aW9uIn19 Which decodes to: {"_rails":{"message":"BAh7CjoLZm9ybWF0SSIIanBnBjoGRVQ6FHJlc2l6ZV90b19saW1pdFsHaQKAB2kCAAU6DHF1YWxpdHlpSzoLbG9hZGVyewY6CXBhZ2UwOg1jb2FsZXNjZVQ=","exp":null,"pur":"variation"}} Is this for analytics? Or some sort of caching?