This section is described as "draft" and under review.

Its not trial use, nor called out for ballot comments. 

When will the review be completed? 

The first sentence is confusing in that it describes mapping between systems using Concept Maps, but ConceptMap maps between ValueSets. This is misleading. 

The table with 3 examples - 2nd column could be updated to better describe the part of the sentence that has "is a code in the code system" - in the implicit code system?

The text above the table doesn't define what implicit means. 

The text below the table, starting with the second paragraph doesn't seem to be about implicit code systems but is describing the code element in a resource, and all the other elements. Which doesn't seem to be specific to FHIR - isn't this the same model (mentioned as a division in the paragraph) in C-CDA templates?

Suggest that this information be moved elsewhere or removed unless it can be adjusted to relate to an implicit code system. 

Also suggest creating a terminology section related to implicit resources in general so the relationships or lack of relationship can be described.  Then we can answer questions like 

1. Can there be an implicit value set drawn from an implicit code system?
2. Is there a CodeSystem resource for an implicit code system?
3. What are the identifiers for an implicit code system?
4. How does one know they are looking at an implicit code system?