[Skim-app-develop] Where the "remember last page" for each PDF are stored?

Hi, dear skim authors

I want to know where the “remember last page” are stored for each PDF.

I know the notes are stored in the extended attributes, but it doesn't
seem to store the last page when I close a PDF file.

When I use my Linux box, I have a script to read “last page opened”
from my PDF reader, and thus I can get an automatic reading tracker,
and I want to do the same on Mac.

Is it stored in a directory? Or need special method to extract from
extended attributes?

Thanks,
slbtty