We're happily accepting bugfixes, style improvements, good refactors and enhancements to documentation.
For the specs, their APIs are considered final and immutable. We do not accept API-breaking changes.
It is possible to propose a new protocol instead. In that case, please open an issue for discussion first, including some motivating use cases.
The contracts are not expected to be packed with features. They're expected to be minimal, reference implementations of the specifications. We do not therefore accept enhancements.