> ## Documentation Index > Fetch the complete documentation index at: https://docs.grounds.gg/llms.txt > Use this file to discover all available pages before exploring further. # PackSet architecture and contracts > Understand ordered packs, catalogs, channels, immutable publications, and selection. A PackSet is the unit of Grounds asset distribution. It binds the ordered ZIP stack, JVM catalog, Minecraft compatibility, integrity hashes, and source provenance into one validated manifest. Consumers select a **channel** or an **immutable release**, rather than constructing a stack of unrelated URLs. For an introduction to individual packs, contributions, catalogs, and their relationship to scenes, read [the content concepts](https://docs.grounds.gg/build/content/concepts.md). ## Pack order and ownership `grounds-global` contains `grounds-content` first and `grounds-platform` second. The later platform pack has higher client priority. The order is part of the contract; preserve it when building an Adventure request. | Repository/module | Responsibility | | - | - | | `library-resource-pack` API | Typed contributions, metadata, vanilla-path claims, and validation policies | | `library-resource-pack` builder | Validate/compose contributions and write deterministic ZIP artifacts | | `library-gui` | Theme declarations and the typed GUI contribution | | `resourcepacks` product | Own final content/platform definitions, artwork, release graph, and publication | | `resourcepacks-catalog` | JVM declarations: `GroundsGuiIds`, `GroundsGuiTheme`, `GroundsAssets`, `GroundsAssetCatalog` | | `resourcepacks-contract` | Strict canonical manifest/channel decoding and validation policy | | `resourcepacks-client` | Background resolution, immutable snapshots, retries, and disk cache | | `plugin-resourcepacks` | Config integration, Velocity delivery, deduplication, and player status | | Forge/Portal | Inspect publications and manage the fixed Stage selection | ## Four identities to keep separate | Identity | Example | Meaning | | - | - | - | | PackSet ID | `grounds-global` | Distribution product | | Publication | Release `v1.1.0` or build's full commit SHA | Immutable publication directory | | Product/catalog version | `1.1.0` or an Edge version | Exact version of declarations and artifacts | | Config document version | `10` as a string | Concurrency token for operator selection changes | An asset catalog pin is exact. A runtime compiled against `resourcepacks-catalog:1.0.0` does not automatically acquire a different catalog because the client receives a newer ZIP. The action catalog has its own independent revision and Maven artifact. ## Distribution layout The CDN origin is `https://cdn.grounds.gg`: ```text theme={null} resourcepacks/packsets/grounds-global/ channels/stable.json channels/edge.json releases/v/ manifest.json grounds-content-pack-v.zip grounds-platform-pack-v.zip grounds-resourcepack-catalog-v.jar builds// manifest.json ... immutable build artifacts ... ``` A channel document is mutable; a release/build directory is immutable. The channel binds a sequence and publication target to a manifest URL, exact SHA-256, and size. Stable targets releases; Edge targets builds. Reused Edge pack URLs may refer to earlier builds only when the final pack hashes and size match; the catalog and manifest remain current-commit objects. ## Manifest schema Manifest schema is **2**. Config and scene schema numbers are separate. | Field | Contract | | - | - | | `schemaVersion` | `2` | | `packSet` | `grounds-global` | | `publication` | `{type: release/build, id}` | | `version` | Product version | | `minecraft` | Exact Minecraft version and resource-pack format | | `catalog` | ID, version, Maven coordinate, file, SHA-256, size | | `packs` | Ordered entries with role, ID, UUID, required, URL, SHA-1, SHA-256, size, format | | `provenance` | Repository and full lowercase commit | SHA-1 is the Minecraft delivery hash. SHA-256 and sizes bind distribution/catalog bytes. A fixed UUID identifies each logical pack; it is not a unique request ID or release identity. The JVM contract rejects noncanonical JSON, duplicate keys, invalid field/type/value combinations, and mismatched origins/publication roots. The resolver checks the expected target, manifest hash/size, and requested source before accepting state. Do not hand-edit a published manifest or treat a hash as permission to accept an arbitrary URL. ## Channel and pin semantics With `source.pin` absent or null, the plugin follows `source.channel`. A release pin overrides the channel but retains that channel in the document for use when the pin is cleared. Release IDs are canonical `v..` without prerelease suffixes; the Portal/Forge request uses the version **without** `v`. A channel switch clears a pin. A release pin does not advance Stable or Edge. A rollback selects an older compatible immutable release; it does not overwrite CDN objects. ## Minecraft compatibility Current product/contract baseline is Minecraft **26.3**, pack format **97**. Forge can inspect historical manifests, but its Stage selection mutation rejects release pins with a different Minecraft version or format. For example, a 26.2/88 publication is inspectable but cannot be pinned through the current Stage selector. > [!NOTE] > > Publication, configuration, proxy resolution, and client acceptance are four distinct states. A successful publish does not activate the product; a successful selection write does not prove every player has accepted it. Continue with [build/publication](https://docs.grounds.gg/build/content/packset-build.md), [client API](https://docs.grounds.gg/reference/plugins/resourcepacks/client-api.md), [Velocity configuration](https://docs.grounds.gg/reference/plugins/resourcepacks/velocity.md), and [operator UI](https://docs.grounds.gg/build/portal/resource-packs.md). ## Implementation sources Verified against the main-branch source on October 14, 2026. * [Product publication](https://github.com/groundsgg/resourcepacks/blob/b6ec976e8ecba665ba97b7d7f457a8a45e93556d/README.md) * [Public contract](https://github.com/groundsgg/resourcepacks/blob/b6ec976e8ecba665ba97b7d7f457a8a45e93556d/resourcepacks-contract/src/main/kotlin/gg/grounds/resourcepacks/contract/PackSetContractJson.kt) * [Object layout](https://github.com/groundsgg/resourcepacks/blob/b6ec976e8ecba665ba97b7d7f457a8a45e93556d/resourcepacks-product/src/main/kotlin/gg/grounds/resourcepacks/product/PackSetObjectLayout.kt) * [Stage compatibility](https://github.com/groundsgg/grounds-forge/blob/fdbfd636bf776e3aeea7e70718e8989da3a437a6/src/resourcepacks/selection.ts) This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.