Google Maps scraping
Google Maps scraping is extracting business listings — name, category, address, phone, website — from Maps results. Maps publishes no email addresses, so the website link is what makes a listing useful.
Maps is the largest business directory that exists, and for local businesses it is close to a census. What it deliberately does not carry is an email address, which is why a raw Maps export is a list of phone numbers rather than an outreach list.
The route to an address runs through the website field. Each listing's site is fetched, its contact, about and imprint pages are checked, and the addresses published there are collected. That second step is where the yield comes from, and where most cheap Maps exporters stop.
Expect the listing-to-address conversion to be somewhere between a third and two thirds, depending on industry and country. Markets with an imprint requirement — Germany and Austria especially — publish addresses far more consistently than markets that route everything through a contact form.
Goes deeper: How to Find Business Emails from Google Maps