It’s a weird way to word it, but sometimes people do direct rehome dogs for free, not that it’s necessarily a good idea. I have had someone offer me a free dog before. I called my mate who works in rescue and asked her to take it for placement with a properly vetted new home. Obviously it would have been safe and well with me, but my own dog was only 18 months at the time and I didn’t want to distress her in any way. EDIT: just remembered I have been offered a free dachshund like… two weeks ago. Still waiting to hear back as I might actually take it. If the shelters are full, people will ask around in their own community and among people they know. It’s not impossible someone who knows her well enough to know she will take care of it might offer her a free dog.