wtf is ainz-unofficial-nai-toolkit?

Ainz Toolkit is a browser userscript that adds a local prompt manager on top of NovelAI's image generation tool, plus the image boards Danbooru, Gelbooru and e621. It runs through Tampermonkey, a free browser extension that lets small scripts modify pages you visit, so there is no separate app to install and no account to create. Once set up, the toolkit gives you a personal library for prompts: character profiles with their own positive and negative text, reusable tag sets, and full snapshots of an entire NovelAI setup that you can restore later. You can save a prompt straight from NovelAI's own input fields, then insert, append or replace text in those fields later with a click, instead of retyping or copy-pasting each time. The Booru integration lets you pull tags and image details directly from a Danbooru, Gelbooru or e621 post, either one at a time or in a batch from a listing page, and choose which categories of tags get imported. Imported images are stored as reusable entries with compressed local preview thumbnails, and the toolkit can group similar images together as variants so you can compare edits or recolors side by side. Other features include a searchable index of every tag used across your saved images, manual and rule based collections for organizing large libraries, and tools for finding duplicate or visually similar images. Everything is stored locally inside Tampermonkey rather than on a server, and the toolkit does not touch NovelAI login credentials or cookies. You can export your whole library as a JSON file for backup. This is a small, unofficial community project maintained by one developer, not an official NovelAI or Booru product, and it currently has just a handful of stars on GitHub.