Mod Package Format

Mod Package Format

This page documents the .modpkg and .fantome mod package formats used by the LeagueToolkit ecosystem.

modpkg

The .modpkg format is the modern, recommended format for distributing League of Legends mods.

Structure

A modpkg file is a binary archive containing:

• Metadata — Mod name, version, authors, description, tags, champions, maps
• Thumbnail — Optional preview image (webp or png)
• Layers — One or more content layers, each containing game files
• Configuration — Layer priorities, string overrides, and other settings

Advantages

• Full metadata support (authors with roles, tags, champions, maps)
• Multi-layer support with configurable priorities
• Thumbnail embedding
• String override support per layer
• Efficient binary format

fantome

The .fantome format is a legacy format used by older mod tools. LTK Manager supports fantome files for backwards compatibility.

Behavior on Install

When you install a .fantome file, LTK Manager:

1. Extracts the archive contents
2. Parses the WAD file structure
3. Converts the content to the internal mod format
4. Stores it as a standard mod in the library

Limitations

Compared to modpkg, fantome files:

• Have limited metadata support
• Don't support multiple layers natively
• Don't include author roles or detailed categorization
• Don't support string overrides

Choosing a Format

• For new mods: Use .modpkg — it supports all features and is the standard going forward
• For compatibility with older tools: Export as .fantome when sharing with users who haven't migrated yet

Both formats can be created using the Creator Workshop pack feature.