ArtifactAppearanceID

The ArtifactAppearanceID is a numeric indicator of which appearance, or "skin," is used by the artifact.

It can be obtained using the API C ArtifactUI.GetAppearanceInfoByID, as well as API C ArtifactUI.GetPreviewAppearance.

Miscellaneous
These items are not obtainable, however still exist within the game files for some reason. They are likely test files.