RHONDA is an informal international community committed to developing interoperable data models for historical decrees, ordinances and other legal regulations.
One of the first pillars is the (ongoing) community-based establishment of shared vocabularies that can be used to classify historical ordinances: subject matters, forms of legislation, legislative offices etc. The establishment of vocabularies goes hand in hand with efforts of providing infrastructural elements that allow researchers to integrate such resources into their respective working environments and workflows.
For the time being, you can find the most relevant information about the community and its activities in the wiki of the PoliceOrdinances repository.