This is the symbol of the Way of Saint James, crafted after the official description and the images published at https://www.xunta.gal/dog/Publicados/2015/20151118/AnuncioG0244-111115-0001_es.html.
It's probably okay to use this image for any non-commercial purpose, especially if it serves to promote activities related to pilgrimage along the Way of Saint James. If you plan to use it commercially, you may want to ask for permission from the Galician Tourist Office (https://www.turismo.gal/contacto-con-turismo-de-galicia?langId=en_US) first.

If you'd like to know more about how the shell was designed, head over to How To draw the Shell  of Saint James.svg
Own work
Marco Perez Kistler