e, if you want to copy the crop area of first crop variant over to all other crop variants. E.g. you have defined 4 crop variants "Desktop", "Landscape", "Tablet" and "Mobile". If you move the crop area of "Desktop", you have to do so with "Landscape", "Tablet" and "Mobile", too, which is a lot of work for your editors. Further it is hard to match the exact position (cropArea) in all other cropVariants.
Run the following command within your Composer based TYPO3 project:
composer require jweiland/sync-crop-areas
Login into TYPO3 Backend of your project and click on Extensions in the left menu.
Press the Retrieve/Update button and search for the extension key sync_crop_areas.
Import the extension from TER (TYPO3 Extension Repository)
There is no configuration for this extensions. Just save the content (tt_content) record to sync the cropAreas over all cropVariants