**** General comments

The ietf-flexe module is a relative small YANG module based on an implementation agreed upon by the OIF Forum. From the YANG point of view, the only problem of the module that I found is that all configuration leaves in the "flexe-client" container are mandatory, which eventually makes the top-level container "ietf-flexe:flexe" mandatory. This violates the requirement in sec. 4.10 of RFC 8407: Top-level data node MUST NOT be mandatory.
  
**** Specific comments

***** Section 2
- The list of requirements would be better formatted as a definition list (<dl>) of xml2rfc v3.
- A spurious character entity representing Unicode character U+12289 appears at the end of the requirement R-Group-02.

***** Appendices
- It would be useful to indicate (at least schematically) that <port-num> leaves are references (leafrefs) to interfaces defined using the ietf-interfaces module.