The Page régulre Séyès is a french standard used in schools to promote better handwriting. Please refer to the french Wikipedia article for details.
For installation of the template, you transfer the files to known positions in the ReMarkable file system using SSH.
For details, please read this guide.
The SVG comes from here, WikiMedia Commons. I’ve loaded it in to a vector editing program to enshure that that it’s dimensions fit the ReMarkable.
There are some additional licencing notes here.