The *.graphql module declaration conflicts with similar declarations in many projects. And in my opinion it's out of the scope of this library. I will try to explain my reasoning:

Unfortunately TypeScript doesn't have an option to exclude types from NPM packages. So these these types are loaded without a way to opt-out.
But many projects might have different needs for *.graphql typings. e.g:

• Add specific modules for every *.graphql file
  The populare tool "Graphql Code Generator" can autogenerate imports for graphql-files, example here: https://graphql-code-generator.com/docs/plugins/typescript-graphql-files-modules#example

• Allow named imports from *.graphql-files (e.g Queries & Mutations) using graphql-tag/loader:
  e.g import { SomeQuery, AnotherQuery } from 'somefile.graphql'.
  One way to allow this is by a simple any declaration:
  declare module '*.graphql';

• Not every typescript project has some loader configured to load *.graphql-files.
  So having these types by default makes incorrect assumptions.

These kind of custom declarations are not possible when using vue-apollo 3.x due to this fixed type which is bundled with vue-apollo.

I propose to just remove the type file again and add docs which explain the situation.

Failing example

import {SomeQuery} from 'somefile.graphql'

export default {
  apollo: {
    someQuery: {query: SomeQuery},
  },
}

Error:

ERROR in MyModule.vue(14,3):
 14:3 Module '"*.graphql"' has no exported member 'SomeQuery'. Did you mean to use 'import SomeQuery from "*.graphql"' instead?
  > 14 |   SomeQuery,
          |   ^
      15 | } from './somefile.graphql';
      16 |

Workaround

Downgrade and pin 3.0.0-rc.7. Packge json:

"vue-apollo": "=3.0.0-rc.7",