Luminar 3 has been released as a successor to Luminar 2018. It is free for Luminar 2018 users.adds a photo library to the editor.
The editing tools are very flexible and it is easy to define new presets.
The catalog is indexing the files in the Finder. Luminar folders are mapped to folders in the Finder. So it has all the advantages and disadvantages of a referenced library.
The support for metadata is very poor. We can assign ratings, flags, color labels, but I have not seen any support to add titles, descriptions, keywords, copy right notices. The Finder in Mojave is showing more metadata than Luminar 3.
We can create albums, but no smart albums. With respect to a thematical structure of the library it does not offer much.
So far, I could not find any tools to structure my photos in Luminar 3 thematically, other than creating albums.