Describe the project you are working on

Godot

Describe the problem or limitation you are having in your project

The fish bone debug, while valuable for some uses, adds a lot of visual noise to a scene and can not be disabled without disabling the entire path debug. This makes scenes with many (crossing) paths very hard to view.

In 2D the fish bone debug is also (very) bad for performance if there are many paths as it uses draw_polyline() for every single sample point instead of e.g. using a mesh.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

Add a ProjectSetting in the debug->shapes menu like for other debug.
Add a editor->debug menu setting to toggle / disable the fish bone part of the debug.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

Add a ProjectSetting in the debug->shapes menu like for other debug.
Add a Editor->debug menu setting to toggle / disable the fish bone part of the debug.

Also add a setting for the fish bone length as it is currently hardcoded.

If this enhancement will not be used often, can it be worked around with a few lines of script?

Debug is core.

Is there a reason why this should be core and not an add-on in the asset library?

Debug is core.