These lists might be of interest to both developers and searchers.
As the U.S. government’s official web portal, we search across all federal, state, local, tribal, and territorial government websites. Most government websites end in .gov or .mil, but many end in .com, .org, .edu, or other top-level domains.
This GitHub page offers details about what is and is not included on the list
Direct to Lists via GitHub:
The GitHub lists will be updated quarterly.
We also recommend taking a look at this interactive/thesaurus version of the list.