The list of changes in Raspbian/Ubuntu/Debian RPi images

Hi,
How can I see the changes which are made for Mender compatible device? Which files are changed and how, which are the new files, etc.?
Is it possible to do this changes manually in the last version of Raspbian image from 2019-06-20, because there is not ready for use Mender image for this Raspbian image version?
How can I use the old Mender image for Raspbian and to update to the new image using Mender Server and Mender Client?

How can I see the changes which are made for Mender compatible device? Which files are changed and how, which are the new files, etc.?

I guess the easiest way is to read the source code of the tool that is used to convert Raspbian images.

You can also read this post to get an idea what changes are done,