They are files/folders in the project directory. For instance, I have a .github directory with workflows and such in it, and it would be nice to see those in the Project navigator. Granted, I can just open them in another application, or use Terminal to open them, but it would be nice if I didn't have to exit Xcode to view files in the project I'm working on. So, the project might look like:
Project/
	.github/
		workflows/
	.gitignore
	SwiftFile.swift
	...
tristanbiesecker
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