Update DEVELOPER.md

Author: twishabansal

DEVELOPER.md

@@ -46,9 +46,11 @@ for every pull request. This workflow primarily verifies that the extension can
 be successfully installed by the Gemini CLI.
 
 Currently, there are no automated unit or integration test suites
-within this repository. All functional testing must be performed manually. All tools
+within this repository. All functional testing must be performed manually. All skills
 are currently tested in the [MCP Toolbox GitHub](https://github.com/googleapis/mcp-toolbox).
 
+The skills themselves are validated using the `skills-validate.yml` workflow.
+
 ### Other GitHub Checks
 
 *   **License Header Check:** A workflow ensures all necessary files contain the
@@ -60,11 +62,6 @@ are currently tested in the [MCP Toolbox GitHub](https://github.com/googleapis/m
 *   **Dependency Updates:** [Renovate](https://github.com/apps/forking-renovate)
     is configured to automatically create pull requests for dependency updates.
 
-## Building the Extension
-
-The "build" process for this extension involves packaging the extension's
-metadata files (`gemini-extension.json`, `BIGQUERY.md`, `LICENSE`) along with the
-skills.
 
 ## Maintainer Information