Which flavor of Marlin did you download from
https://marlinfw.org/meta/download/ ?
If you downloaded 2.1.2 then the one to compare against is on the releases page
https://github.com/MarlinFirmware/Marlin/releases which has a pointer on the
https://github.com/MarlinFirmware/Marlin page.
If you downloaded bugfix-2.1.x then you downloaded a snapshot of last night's bugfix-2.1.x. If you click on the
Code button on
https://github.com/MarlinFirmware/Marlin you'll get the newest bugfix-2.1.x.