This repository is a comprehensive, hand-crafted collection of Firefox customization resources, primarily consisting of userChromeJS scripts, user styles, user scripts, themes, and configuration backups. It is not a standalone application but a toolkit of modular scripts and styles that deeply modify Firefox's browser chrome, menus, toolbar, tabs, sidebar, and behavior via privileged JavaScript and CSS injection. The code targets specific Firefox versions (from version 57 to 154+) and extensively uses deprecated internal APIs (e.g., `Components`, `Cu.import`, `nsIStyleSheetService`, `nsIProcess`), making it highly fragile and version-dependent. Many scripts are marked as archived or no longer updated. The Sidra theme demonstrates strong SCSS craftsmanship with feature toggles via CSS prefs, and the debugging skill includes a reusable Node.js RDP client. Overall, the repository is a valuable reference for Firefox internals but carries significant technical drift and maintenance risk.