Polymer 2.x code can be documented using JSDoc-style comments, like Polymer 1.x code. Documentation tools for Polymer 2.x are still under development. Information about the new documentation tools will be available in a future release.
The Polymer 1.x tools (specifically,
iron-component-page) won't work for Polymer 2.x,
but the general documentation rules are the same as that described in
Document your elements in the Polymer 1.x docs.