Overriding assumptions + Custom dimensions

Our development team is interested in customizing behavior of the currently supported dimensions. My current understanding is that there is not a way to "extend" this when creating your own project and pulling in Duckling as a dependency; one would need to fork the project and make changes to the source code.

Is this understanding accurate? If not, how could a user override dimensions outside of editing the dimension source code?

CC @pcgreat

The issue does not name files, tests, or an entry point. Start by reviewing how Duckling dimensions are exposed to projects using it as a dependency and the existing discussion, then establish whether external overrides or custom dimensions are supported and what acceptance criteria a solution must meet.

Written by the indexing model from the issue text.