Final cut pro library size

[Le0M]

Hi everyone,
I'm quite new to FCP, and after completing a project a while ago, now I'm back to it cuz I wanted to create subs for it.
I opened the 12GB library, but to my surprise, except for a very few, all files where marked as missing.
Now, I already managed to relink them using an external backup drive; but what I don't understand is why the library is 12GB, if all files where missing.
Could someone kindly explain to me what that data could be, and why it's so big even without having those files? Shouldn't it just keep the settings of everything I've done/modified and eventually apply these settings onto the original files (if properly linked) ?

Thanks a lot in advance!

 

[HDFan]

Find the project which is so large.





Open the package to see where the space is being used.

 

[Le0M]

Find the project which is so large.

View attachment 1996645

View attachment 1996646

Open the package to see where the space is being used.

View attachment 1996647

Thanks for your suggestion.
I found the file that occupy the entire space, and it's quite weird, cuz it's just one of several video I personally shot, so I wonder why this is the only one in the "High Quality Media" folder. What does that even mean, really?
What would happen if I deleted the single file?

 

[HDFan]

Create optimized and proxy files in Final Cut Pro for Mac

In Final Cut Pro for Mac, create optimized and proxy versions of your media files to increase editing performance and conserve storage space.

support.apple.com

I'm not an FCP expert so I'd be sure to have backups before I deleting the Proxy media.