The Outline feature in CotEditor extracts specific parts of your document based on the syntax definition and generates a structured list.
The generated outline appears in both the navigation bar and the inspector.
The Outline menu is a pop-up menu appears in the navigation bar above the editor. It shows the nearest outline item above the insertion point. Selecting an item moves the insertion point to that location and scrolls the editor accordingly.
In the CotEditor app 
on your Mac, open a document.
Choose View > Show Navigation Bar.
The Outline inspector is a table of contents style list that appears in the Outline pane in the inspector. It gives you a quick overview of the document’s outline and lets you jump to the corresponding part in the editor by clicking an item in the list.
In the CotEditor app on your Mac, open a document.
Do one of the following:
Choose View > Inspector > Outline.
Select Inspector in the document toolbar, then select the Outline pane (list icon).
To move to the position of an outline item in the editor, do one of the following:
Move to a specific outline item:
Select the item in the navigation bar or in the Outline inspector.
Move to the previous or next outline item from the current insertion point:
Find > Select Previous/Next Outline Item.
Click a arrow button next to the Outline menu in the navigation bar.
The rules that determine which items appear in the outline and how their titles are extracted are defined per syntax. You can configure these rules in the Syntax definition > Outline settings.