I use Xcode 9.0. Some folders icons in my Xcode project have dark triangles in bottom left corner - for example, \"0. Login\", \"Frameworks\", \"Products\", \"Pods\". What d
Folders without dark triangles exist as a group in your project and also (what is new in Xcode 9) exist as a folder in file structure.
Example: After double-click in your project navigator you can see menu:
For New Group Xcode create group in project navigator and create folder in file structure (in finder) and of cource for New Group without Folder create only group.