Found this today: https://blogs.gnome.org/mcatanzaro/2017/08/13/gnome-3-26-core-applications/

Should help us in avoiding ambiguity regarding which apps are classified as core GNOME apps and which aren't.

Here is the entire list as it is right now:

• Archive Manager (File Roller)
• Boxes
• Calculator
• Calendar (gnome-calendar, not california)
• Characters (gnome-characters, not gucharmap)
• Cheese
• Clocks
• Contacts
• Disk Usage Analyzer (Baobab)
• Disks (gnome-disk-utility)
• Document Viewer (Evince)
• Documents
• Files (Nautilus)
• Fonts (gnome-font-viewer)
• Help (Yelp)
• Image Viewer (Eye of GNOME)
• Logs (gnome-logs, not gnome-system-log)
• Maps
• Music
• Photos
• Screenshot
• Software
• Simple Scan
• System Monitor
• Terminal
• Text Editor (gedit)
• To Do
• Videos (Totem)
• Weather
• Web (Epiphany)