You mean "proxies." That is a major topic with the Appraisal Institute 7-hour USPAP course for the 2024-25 USPAP. So, as a Certified Residential Appraiser, you shouldn't be asking such a question. But in short, a proxy for race or other protected personal characteristics is something that is not itself a protected characteristic, but can be used as a tool to discriminate against a protected characteristic. A proxy is usually a feature that has a high correlation or similarity with a protected personal characteristic. The courts may have decided that specific phrases or words have been commonly used in the past to indicate a significant minority presence in neighborhoods, such as the use of "diverse" or "up-and-coming" and so on. (These are specifically code-words, which are a kind of "proxy.")
So as I said in my final review ot the Appraisal Institute 7-Hour course I just finished: "What good does it do to spend so much effort and time trying to modify the behavioral characteristics of appraisers to avoid bias, when they can't even provide an accurate value. All they know is simple linear regression and matched pairs analysis, and most don't even understand how to use these elementary techniques properly."
At least I am done with the course now. It is very boring to wade through.
Now I can continue completing my current Home/Office automation project: Raspberry Pi 5, HomePod, Homebridge, Amazon Echo, Kasa KP125M Matter Plugs,...
And then there is the question of getting a 3D printer.
My oldest daughter beat me to the draw with Home Automation and 3D Printers. She is always very busy all the time - so she automated much of their 5k sf home - she's a good DIY electrician, actually.
And meet your new friends Alexa and Siri. They are always willing to talk to you in the nicest voice. They can turn your Kasa plugs on and off by name, close your open files, close your apps, put your computer sleep, wake it up, .... all you have to do is figure out get past the barriers and obstacles that pop up. - And they can serve as a targeted Intercom: "Alexa, tell Bert's Echo that he needs to come downstairs and fix the TV."