Added: It is a column, have a look at Preferences->Add your own columns.
To the extent that it's possible, I ignore it.
I renamed the custom column I had from 'pages/Pages' to 'cc_pages/CC Pages' and made necessary adjustments to the Count Pages plugin, Book Details settings etc. And I customised the bookshelf view settings to suit my preference for minimalism:
I wish there was a setting for shelf colour, dark brown on grey wash looks awful.
The page/Pages built in column is stored in the book-pages-link table in the metadata.db database.
BR