XMP files are “sidecar” files that Mylio Photos creates when changes have been made to your photos. These files are very small and only contain the instructions on how to edit your file or additional metadata about the file.
Because Mylio Photos is a nondestructive application, your original images will not be changed. Instead, changes will be recorded to the XMP file and the XMP file changes are applied to your original image on export.
XMP files are a standard for recording metadata for images and are used by many applications. Changes made in Mylio Photos can be read by most applications that utilize XMP files. If you wish to apply metadata to the original (non-raw) image, you can do so with Mylio Photos’ Save Metadata to File option.