> ## Documentation Index
> Fetch the complete documentation index at: https://docs.qomicex.top/llms.txt
> Use this file to discover all available pages before exploring further.

# Glossary

## Glossary

Terms that recur throughout the launcher documentation, explained in one place.

## Game and instances

| Term | Explanation |
| :- | :- |
| **Instance (Instance)** | A self-contained copy of the game (game files + mods + saves + settings). One instance corresponds to one version directory under `versions/` |
| **Game directory (Game directory)** | Commonly known as `.minecraft`; the root directory holding game files. The launcher can manage several game directories at once |
| **Data directory (Data directory)** | Where the launcher stores its own configuration, cache, and logs; separate from the game directory |
| **Version isolation (Version isolation)** | A mechanism that isolates each instance's mods, saves, resource packs, and other data so multiple instances do not mix files |
| **Complete missing files (Repair files)** | Scans an instance for missing game files (libraries, assets, client.jar) and downloads them automatically |

## Loaders and modpacks

| Term | Explanation |
| :- | :- |
| **Vanilla (Vanilla)** | The official game with no Loader (Loader) |
| **Loader (Loader)** | A framework that loads mods on top of vanilla: **Forge**, **Fabric**, **NeoForge**, **Quilt**. Mods for different loaders are generally not interchangeable |
| **Mod** | A modification that changes game behavior, installed per loader |
| **Modpack (Modpack)** | A fully preconfigured game environment: game version + loader + a full set of mods + settings, installed in one click |
| **Resource pack (Resource packs)** | Replaces the game's visuals and sounds (formerly called "texture pack") |
| **Shader pack (Shader packs)** | Works with a shader loader to add lighting and shadow effects |
| **Data pack (Data packs)** | Vanilla data extensions at the world level; they travel with the save |
| **Schematic (Schematic)** | A building blueprint file for the Litematica mod |

## Accounts and authentication

| Term | Explanation |
| :- | :- |
| **Microsoft login (Microsoft sign-in)** | OAuth authorization with a genuine Microsoft account |
| **Offline login (Offline login)** | Verifies only the username; used for singleplayer or offline servers |
| **External login (Yggdrasil) (External login)** | Third-party authentication services (such as LittleSkin or Tongyitong) that emulate official verification with their own account systems |
| **Tongyitong (Unified Pass)** | The name of one Yggdrasil external login service |

## Multiplayer

| Term | Explanation |
| :- | :- |
| **Host (Host)** | The player who creates a multiplayer room and manages players and the mod list |
| **Room code (Room code)** | A short code the host shares with friends; it is used to join the room |
| **NAT** | The address translation type of the router, which determines how easy a direct P2P connection is; strict NAT may require relaying |
| **Mod consistency (Mod consistency)** | Before joining, the launcher compares the host's mod list with your local one so the game does not crash over mismatched mods |

## Diagnostics

| Term | Explanation |
| :- | :- |
| **mclo.gs** | A public log sharing service that turns long logs into short links you can paste into issues or chats |
| **JVM arguments (JVM arguments)** | Launch arguments passed to the Java virtual machine, often used to adjust memory and garbage collection |


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