Thanks for the info!
I tried to open the library in photos without success.
But your answer sent me in another direction. I have an app called Luminar Ai and I imported my "pictures" folder when I set the app up initially. And the aperture library was in that folder.
So when I looked at the contents of the aperture library in Luminar Ai, there were thousands of pictures there! Unfortunately there were many, many duplicates (15,091 to be exact). However, in the Masters sub- folder, there are only 3274. I am not sure what metadata might be present.
So from your comment above, I should be able to do some recovery work from the Masters folder. There is also a Previews folder and a thumbnails folder with images as well.
Any guidance on how to work with these folders to recover as much as possible, would be appreciated.
Thanks for all of your help.
Bill