What are the values in _ga cookie?

@virginie 

The _ga cookie is used by Google Analytics to distinguish unique users by assigning a randomly generated number as a client identifier. The values in the _ga cookie include:

1. GA1: This is the version of the cookie.
2. XXXXX: This is a unique identifier assigned to the user by Google Analytics. It is a string of numbers and letters that is randomly generated.
3. YYYYYY: This is a timestamp that indicates the time that the user first visited the site. It is in Unix format and represents the number of seconds since January 1, 1970.
4. ZZZZZZ: This is another timestamp that indicates the time that the cookie was created. It is also in Unix format and represents the number of seconds since January 1, 1970.

For example, a typical _ga cookie value might look like this: GA1.XXXXX.YYYYYY.ZZZZZZ.