How to Transfer slo-mo video from one mac to other in photos.app with slow motion edits options?
In Finder:


Create a folder for the media you want to transfer.

In the Photos app:


Select the media that you want to transfer.
In the menu bar, select File &gt; Export &gt; Export Unmodified Original For...
Select Export
Choose folder from step one

Transfer the folder from step one to the Mac where you want to import the photos
In the Photos app on that Mac:


In the menu bar, select File &gt; Import...
Select the folder you exported from step one
Select Review for Import
Follow the dialog.

Enjoy.


(But do note: If you made a modification to the slow motion segment, it will be reset to the default after export. I'd love for this to be amended, but I suppose we're beholden to Apple for that...)