Does FCPX crop original 2.7k file or transformed 1080p file (in project) when stabilizing?

Hello!

A question came to mind today when editing a small project. I usually film in 2.7k (GoPro, Mavic) which I import into my FCPX library, but I do most projects in 1080p. When I stabilize my trimmed clips in the timeline/project, my clips obviously get somewhat cropped, depending on the amount of stabilization applied. But does this cropping occur on the original 2.7k file, or the "transformed" 1080p-clip in my timeline? Does it matter?

A similar question would be if I choose to crop the said file, will FCPX then "zoom" into the original 2.7k clip, thereby not losing any pixels, or does FCPX crop on the transformed 1080p-file in the timeline and thereby "zooming" into the 1080p-clip --> upscaling?