Note: for a more in-depth explanation, see RFC-0089.
The core realm is the highest-level CFv2 component realm holding other packaged components. The contents of this realm may vary across products, as certain parts of our platform belongs in certain configurations and not in others.
The exact contents of the core realm are controlled by a GN argument that is set in the product definitions (located in //products). This argument contains a list of GN targets. These targets are walked at GN metadata time to find CML shard files to be merged with a common base to create the core realm.
The common portions of the core realm which are shared across all products are included in
Any components or capability routes included in this file will be part of all Fuchsia products. Core shard operations are only additive. Therefore if a new product is added which wishes to exclude a portion of this file, the to-be-excluded contents should be removed from this file and added to a new core shard.
The optional portions of the core realm are included in separate CML files, and are pointed to by the
core_shard template defined in
Any product wishing to merge a shard into its core realm should include the shard‘s GN target in the
core_realm_shards argument in the product’s