A residential proxy routes traffic through a real consumer connection — often a phone or a home router enrolled by an app its owner installed — so that the request arrives from an address that genuinely belongs to a household. It is the standard way of defeating exactly the checks the IP product performs.
What Spaw answers
Nothing. is_datacenter, is_vpn and is_relay all answer false, because the address really is a consumer address, and is_anonymous follows them. There is no field for this and there will not be one from open data.
Why the entry exists anyway
Because the honest reading of a clean IP answer depends on knowing it. An address with no flags is not evidence of a real person at home; it is the absence of evidence of anything else. Residential proxy networks are detected commercially by traffic behaviour, and no free, openly-licensed dataset lists their addresses — so Spaw names the dataset behind every field it publishes and publishes nothing here.
Where this matters, the answer is not a better IP feed. It is another signal: a disposable email address, a virtual phone number, or the cross-signal check that names two weak signals coinciding.