I created this with the Click2shp tool (http://gis.ucla.edu/apps/click2shp/), making my best informed assumptions about how to translate the HOLC map (http://offcite.org/hazardous-the-redlining-of-houston-neighborhoods/) from 1930 to today's Houston. Then I used the SHP to GEOJSON converter (https://mygeodata.cloud/converter/shp-to-geojson) to compile all of these into the geojson object in this repo.
I would welcome any corrections the community has to offer. While I have done my best to learn more about Houston history to understand the street name changes and neighborhood history, I imagine I made some mistakes.
As I mentioned on houston.definitedeclining.org, this geojson file is free for non-commercial public use, though I would very much appreciate it if you would email me at evan@evanoneil.studio and let me know what applications you have found for it.