diff --git a/packages/gatsby/cache-dir/gatsby-browser-entry.js b/packages/gatsby/cache-dir/gatsby-browser-entry.js
index 65218f27844e2..c2bfd3e2b7d6c 100644
--- a/packages/gatsby/cache-dir/gatsby-browser-entry.js
+++ b/packages/gatsby/cache-dir/gatsby-browser-entry.js
@@ -23,5 +23,4 @@ export {
 
 export { graphql, prefetchPathname }
 export { StaticQuery, StaticQueryContext, useStaticQuery } from "./static-query"
-export { Slice } from "./slice"
 export * from "gatsby-script"
diff --git a/packages/gatsby/src/utils/webpack.config.js b/packages/gatsby/src/utils/webpack.config.js
index 63906e9afbbc5..8d9f04a997b5f 100644
--- a/packages/gatsby/src/utils/webpack.config.js
+++ b/packages/gatsby/src/utils/webpack.config.js
@@ -227,7 +227,6 @@ module.exports = async (
             })
         ),
         "global.hasPartialHydration": isPartialHydrationEnabled,
-        "_CFLAGS_.GATSBY_MAJOR": JSON.stringify(_CFLAGS_.GATSBY_MAJOR),
       }),
 
       plugins.virtualModules(),
diff --git a/patches/v5/3-remove-static-query-component.patch b/patches/v5/3-remove-static-query-component.patch
index 1a7eb7a4e2820..c01ab591156c8 100644
--- a/patches/v5/3-remove-static-query-component.patch
+++ b/patches/v5/3-remove-static-query-component.patch
@@ -8,7 +8,7 @@ index c2bfd3e2b7..9e0f1205bf 100644
  export { graphql, prefetchPathname }
 -export { StaticQuery, StaticQueryContext, useStaticQuery } from "./static-query"
 +export { StaticQueryContext, useStaticQuery } from "./static-query"
- export { Slice } from "./slice"
+ export * from "gatsby-script"
 diff --git a/packages/gatsby/cache-dir/static-query.js b/packages/gatsby/cache-dir/static-query.js
 index e31cebb08a..cef8ab70ed 100644
 --- a/packages/gatsby/cache-dir/static-query.js
diff --git a/patches/v5/5-slices-api.patch b/patches/v5/5-slices-api.patch
index 4e1bc7a88725a..41f6cc10bb891 100644
--- a/patches/v5/5-slices-api.patch
+++ b/patches/v5/5-slices-api.patch
@@ -1,5 +1,15 @@
+diff --git a/packages/gatsby/cache-dir/gatsby-browser-entry.js b/packages/gatsby/cache-dir/gatsby-browser-entry.js
+index 9e0f1205bf..f0a7dcb841 100644
+--- a/packages/gatsby/cache-dir/gatsby-browser-entry.js
++++ b/packages/gatsby/cache-dir/gatsby-browser-entry.js
+@@ -23,4 +23,5 @@ export {
+ 
+ export { graphql, prefetchPathname }
+ export { StaticQueryContext, useStaticQuery } from "./static-query"
++export { Slice } from "./slice"
+ export * from "gatsby-script"
 diff --git a/packages/gatsby/index.d.ts b/packages/gatsby/index.d.ts
-index 57c92929c1..10763ffa32 100644
+index db2b6a78c1..f0e7745e01 100644
 --- a/packages/gatsby/index.d.ts
 +++ b/packages/gatsby/index.d.ts
 @@ -182,6 +182,30 @@ export type HeadFC<DataType = object, PageContextType = object> = (
@@ -33,7 +43,7 @@ index 57c92929c1..10763ffa32 100644
  /**
   * Props object passed into the [getServerData](https://www.gatsbyjs.com/docs/reference/rendering-options/server-side-rendering/) function.
   */
-@@ -1227,6 +1251,14 @@ export interface Actions {
+@@ -1207,6 +1231,14 @@ export interface Actions {
      option?: ActionOptions
    ): void
  
@@ -48,19 +58,20 @@ index 57c92929c1..10763ffa32 100644
    /** @see https://www.gatsbyjs.com/docs/actions/#deleteNode */
    deleteNode(node: NodeInput, plugin?: ActionPlugin): void
  
-@@ -1664,6 +1696,12 @@ export interface Page<TContext = Record<string, unknown>> {
+@@ -1642,6 +1674,13 @@ export interface Page<TContext = Record<string, unknown>> {
+   context?: TContext
+   ownerNodeId?: string
    defer?: boolean
- }
- 
++  slices?: Record<string, string>
++}
++
 +export interface SliceInput<TContext = Record<string, unknown>> {
 +  id: string
 +  component: string
 +  context?: TContext
-+}
-+
+ }
+ 
  export interface IPluginRefObject {
-   resolve: string
-   options?: IPluginRefOptions
 diff --git a/packages/gatsby/src/redux/actions/restricted.ts b/packages/gatsby/src/redux/actions/restricted.ts
 index cb105dfa6d..0ee5d3eda7 100644
 --- a/packages/gatsby/src/redux/actions/restricted.ts