Customising the Google Sitemap Filename

The Permalinks Cascade lets you pick out a filename of your choice to assign to the Google Sitemap. Looking into the plugin's dashboard you will find, after having clicked on 'Configure', a text field that will let you enter an alphanumeric filename that can include hyphens, too — submitting a filename with any other character in it will result in the string to be reset to its default value.

As The Permalinks Cascade will remind you, whenever you change the filename of the Google Sitemap you will also have to re-submit its URL to Google through the Google Search Console.