Sorry, but that ain’t a prayer rug. It looks like a torn piece of quilt. Prayer rugs look like small oriental carpets and don’t have arabic writing on them since it would be disrespectful, in their eyes, to stand on words they hold sacred.
Ok. Let’s assume you’re right. It is not a Muslim prayer rug. Doesn’t change anything for me. A rug with Arabic writing on it is found on the border. That tells me all I need to know. What the rug was used for is irrelevant.