The idea behind this new function is identical to that of Apple, informing potential users of what data is collected and for what purpose. An example of transparency that will try to give users control over their data.
As this is a big change, Google Play is informing in advance of this measure, which will be taken in the next year. The developers will inform in the files of their applications the data they use, risking in case the truth is not told to measures by Google Play.
As for the timeline that will mark this new function, it will begin this summer, informing the developers of the new requirements. Said developers may begin to include the requested information at the end of 2021 and it will not be shown to end-users until early 2022. As of the second quarter of 2022, developers will have to provide this information either to update an existing app such as for new apps.