User Guide: Confirm rule for leading colon on project path

Section 57.5, “Project and task paths” starts with the following: >A project path has the following pattern: It starts always with a colon, which denotes the root project. The root project is the only project in a path that is not specified by its name. The rest of a project path is a colon-separated sequence of project names, where the next project is a subproject of the previous project.

In my experience, this is stricter than reality. I find that Gradle treats “docs:userguide” the same as “:docs:userguide”. Is it supposed to work this way, or is it supposed to work as written in the User Guide?

AFAIK, the only exception is the ‘include’ method in ‘settings.gradle’, which doesn’t require a leading colon.

Ok, then so far we have two “exceptions”. The command line and the “include” method. Is there any place where it’s actually required, or is it optional everywhere this pattern can be specified?