Swift annotation "tag"

The - Tag: annotation is used to locate specific places of your own code. You can include it as part of symbols documentation in Swift. E.g. you may add a Tag marker in some Swift file next to a function:

/// - Tag: myFunction
func myFunction() {
  print("My function is called")
}

In another file you can refer to this exact place in the code as part of another Swift entity documentation:

/// Uses [myFunction](x-source-tag://myFunction) internally
func anotherFunction() {
  myFunction()
}

When using the Quick Help popover on anotherFunction in Xcode, you get an interactive reference (under myFunction text), which takes you to the file (and line) where the /// - Tag: myFunction is located: