Make cookies more configurable, to appease stricter browser policies

[atom-box]

For quite a while there have been warnings in the browsers about the end of 3rd party cookies.
Now, Google will phase out any 3rd party cookies with the beginning of 2025
https://developers.google.com/privacy-sandbox/3pcd

Since our Matomo installations are running on a sub domain of example.com (like "analytics.example.com" or "matomo.example.com") we will have some 3rd party cookie issues with our other domains like "foo.com" or "bar.com" etc.

There is a solution for such kind of issues, when using the "CHIP" method.
https://developers.google.com/privacy-sandbox/3pcd/chips
https://developer.mozilla.org/en-US/docs/Web/Privacy/Privacy_sandbox/Partitioned_cookies

Currently, Matomo cookies look like this:

We propose that it would be great if Matomo will add settings so that the cookie can have

• Set the "SameSite" to "none"
• Set the "Partitioned" flag
• Set the "Secure" flag
• Example: Set-Cookie: __Host-example=34d8g; SameSite=None; Secure; Path=/; Partitioned;

Or will be a way inside Matomo to define the cookie(s) flags/attributes, that Matomo send to the browser?

[randy-innocraft]

Hi @atom-box . Thank you for creating the issue and bringing this to our attention, that's very appreciated. We have reviewed and triaged the problem internally, and we have confirmed it is an issue. Our team will prioritise this, and we will update you on the progress here when we have an update to share. If you have any further information or questions, please feel free to add them here.