I checked and
@nesym is correct. I can confirm that.
Download the free plugin from Official WP repo:
https://wordpress.org/plugins/wordpress-seo/
Navigate to:
wordpress-seo\css\main-sitemap.xsl
You can see on line 74:
Generated by <a href="
https://yoa.st/1y5" target="_blank" rel="noopener noreferrer">Yoast SEO</a>, this is an XML Sitemap, meant for consumption by search engines.<br/>
The above line is CORRECT (because that's the official WP release).
If you download the nulled version (FREE), and navigate to:
wordpress-seo\css\main-sitemap.xsl
You can see on line 74:
Generated by <a href="
https://seotravel.net/yoast" target="_blank" rel=".noopener .noreferrer">Yoast</a> <a href="
https://seotravel.net/seo" target="_blank" rel=".noopener .noreferrer">SEO</a>, this is an XML Sitemap, meant for consumption by search engines.<br/>
Also, seotravel.net has nothing to do with YOAST.com. You can see the who.is information of seotravel.net.
If you like to check what the Yoast website uses, you can go to:
Now go to your domain. For example:
You will see that it's different. Just like
@nesym mentioned.
Please share clean files the next time. Thank you.