Many of the advertising companies who use the internet to offer and advertise their products or services often use a large number of techniques to profile users to those who want to reach, which from that point of view is not bad, but due to the abuse of this, more and more advertising companies want to obtain more information and above all as precise as possible for it and in this part many users are not according to share, much less allow it to be stored on the servers of the ad networks.
One of the main identifiers that is usually used is the User-Agent, which basically shows the data of the name of the browser, its version number, name and the version of the operating system used, among other data.
It is because of that on the Chromium forums, Chromium developers proposed to unify and freeze the content of the HTTP header User Agent, which transfers the name and version of the browser, as well as restricting access to the navigator.userAgent property in JavaScript.
At the moment there is no plans to remove the User-Agent header yet, but the initiative has already been proposed and is supported also by Edge and Firefox developers and is also already implemented in Safari.
One of the main reasons to unify the removal of the User-Agent header is its use for passive fingerprinting, as well as the practice of spoofing the header with less popular browsers to ensure the performance of individual sites (for example, Vivaldi is forced to present sites like Chrome).
At the same time, the fake User-Agent in browsers second level too it is stimulated by Google itself, since User-Agent blocks the entrance to its services.
Unification also allows you to get rid of the outdated and nonsensical User-Agent string hint of attributes such as "Mozilla / 5.0", "like Gecko" and "like KHTML".
The User-Agent header is proposed as a replacement for the mechanism User-Agent Client Hints, which involves selective return of data in a browser specific and system parameters (version, platform, etc.) only after a request from the server and giving users the ability to selectively provide similar information to site owners.
When using user agent client hints, the identifier is not passed by default without an explicit request, making passive authentication impossible (by default, only the browser name is specified).
Regarding active identification, the additional information given in response to the request depends on the browser settings (for example, the user can refuse to transfer data) and the transmitted attributes cover the same amount of information as the current user agent string.
The volume of data transmitted is subject to the privacy limit, which determines the limit of the amount of data that can potentially be used for identification; If more information can lead to an anonymity violation, further access to certain APIs is blocked.
Technology evolves as part of the Privacy Sandbox initiative previously submitted intended to achieve a compromise between users' need to maintain confidentiality and the desire of ad networks and sites to track visitor preferences.
According to the current plan, access to property navigator.userAgent will be deprecated in Chrome 81 (scheduled for March 17).
Chrome 81 will stop updating the browser version and will unify the versions of the operating system and Chrome 85 will unify the line with the identifier of the operating system (It will only be possible to determine the desktop and mobile operating system, and for mobile versions, information on typical device sizes will probably be provided.
If you want to know more about the discussion that took place in the Chromium forums, you can consult it In the following link.