Apple's metadata filesystem - stores file metadata in seperate database, import for common and customized file metadata, sophisticated api and command line query
Wasabi is an effort to create a unified searching and metadata storage specification for the free desktop. This document contains draft specs meant for further discussion.
M. de la Iglesia. document | archive | disseminate graffiti-scapes. Proceedings of the goINDIGO 2022 International Graffiti Symposium, Seite 175-187. (2023)