text: Today’s Question: Are there any Lightroom ratings that are visible in other software (such as star ratings)? What about color labels and pick flags? Any others that aren’t?
  Tim’s Quick Answer: Yes, as long as you save metadata updates to your source image files the star ratings and color labels will be visible to other software applications that display photo metadata. However, any pick and reject flags you assign will not be available outside of Lightroom Classic, even if you save metadata to your photos.
  More Detail: There are two factors involved in making sure that the metadata updates you apply in Lightroom Classic are visible in other software applications. First, you need to make sure you are using metadata fields that are part of an established metadata standard. Second, you need to enable the option to save metadata to your source image files.
  When it comes to ratings used to identify favorite (or not-so-favorite photos) in Lightroom Classic, both star ratings and color labels are included in established metadata standards. That means that most (if not all) image-management software would be able to understand the values you have assigned to these metadata fields in Lightroom Classic. However, the pick and reject flags available in Lightroom Classic are not part of a metadata standard, and would therefore not be available to other software applications.
  In order for standard metadata updates to be visible to other software applications, you need to make sure that Lightroom is writing those updates to the photos themselves. By default Lightroom only saves metadata updates within the catalog. However, if you turn on the “Automatically write changes into XMP” checkbox on the Metadata tab of the Catalog Settings dialog, standard metadata updates will also be written to the source files in addition to being updated in the Lightroom catalog. Note that in the case of proprietary raw captures the metadata updates are actually written to XMP “sidecar” files rather than the original capture file.