Contributing

You can contribute in two ways:

Tooling. If you have an idea for ways we could make this data available that is not already covered, you can start an issue discussing your idea. Let's talk about it first --- if we like it, we'll be more than happy to figure out a good way to hook up your idea to this repo.
Changes to dataset. If you find that some data is incorrect in some way, please feel free to open a pull request directly. Make your changes in the appropriate data files and add links to document your changes. We prefer official sources (e.g. those managed by the country ccTLD managers themselves.)

Known dataset problems

This section contains open problems that we would love contributions to, in order to have as complete a dataset as possible.

Japanese geographical 2nd and 3rd level domains (c.f. .jp on Wikipedia).
If you know how they work and how we can get an exhaustive list, that would be amazing!
UK school disctrict names (c.f. .uk on Wikipedia)
If you know how the *.sch.uk school districts are allocated, it would be interesting to be able to build an exhaustive list of them here. It seems (?) that third level are only used for categorization/rarely hold a site themselves, e.g. enfield.sch.uk.
US states and territories (c.f. .us on Wikipedia)
The US has a lot of 2lds for states and 3lds for localities. If there is a way to find an exhaustive list that would be great.
Countries without primary sources. A lot of the lists of 2nd-level domains for countries currently rely on the work of volunteers on Wikipedia, and have used Wikipedia articles as sources. It we can find primary sources (preferably the official source in each country on country code domain management) and use those instead that would be great.