Pretty sure extrafanart is just a directory of fanart relative to a parent directory.that skins know to look for, there is nothing written to the media library db so not sure what this addon is supposed to do.
Texture Cache Maintenance Utility: Preload your texture cache for optimal UI performance. Remotely manage media libraries. Purge unused artwork to free up space. Find missing media. Configurable QA check to highlight metadata issues. Aid in diagnosis of library and cache related problems.
