[Alice Fisher]

Hello
I’m new to Creative Cow so my apologies in advance if i’m in the wrong area!
I have just finished up an edit for a client in FCPX. They are happy and have asked for the final hires film. That’s fine. However they also asked for the ‘open files’. I wasn’t sure what this meant and they came back to me with ‘so that we have the ability to take out slides and replace with other language variants in the future…’
Can anybody help and tell me how i send the film in this format?
Thanks in advance.