The System Pages list is generated from your active modules and settings - for example Meal Packs, By The Pound, Choose Subscriptions, A la carte, Catering and View Catering Menu, Wholesale, Grab&Go, Custom Meals, Gift Card, Purchase Credit, Extras, Products, Real Time, View Menu Page, Select Meals, My Subscription, Store Menu, Pickups (when pickups are allowed), Proposals, Contacts and Blog. The titles follow the module names you set in Client Config. Custom Pages lists every page created in the CMS, Meal Categories links to the A la carte page pre-filtered on a category, and Product Categories to the products page filtered on a product category.