Update internal docs

Author: 36degrees

README.md

@@ -16,6 +16,8 @@ The original history from the spike is preserved in the `from-govuk-design-syste
 
 [Read issue #22 for more information](https://github.com/alphagov/govuk-prototype-kit-docs/issues/22#issuecomment-1162876785).
 
+In September 2026 [the documentation was converted to a static site](https://github.com/alphagov/govuk-prototype-kit-docs/pull/312).
+
 ### Security
 
 GDS is an advocate of responsible vulnerability disclosure. If you’ve found a vulnerability, we would like to know so we can fix it.

internal_docs/deploys.md

@@ -1,17 +1,22 @@
-# Deploys
+# Deployment
 
-This repo uses [Heroku automatic deploys] to deploy the latest code in the
-`main` branch directly to https://prototype-kit.service.gov.uk.
+## Production
 
-The custom domain is managed by GOV.UK, see [ticket #71] for more details. We
-redirect users from the Heroku domain to the custom domain when the
-`HEROKU_APP_NAME` and `HEROKU_CUSTOM_DOMAIN` environment variables are set,
-which we set by hand as config vars in the Heroku app dashboard.
+The `main` branch of this repo is continuously [deployed to Netlify using their GitHub integration](https://docs.netlify.com/build/git-workflows/overview/).
 
-Deployments are configured manually using the dashboard for the
-[govuk-prototype-kit-docs pipeline]. To check the configuration or any
-deployment issues, log into Heroku using the team credentials in Bitwarden.
+The site is owned by the "GOV.UK Design System team in Netlify.
+
+The custom domain is managed by GOV.UK, see [ticket #71] for more details.
 
-[Heroku automatic deploys]: https://devcenter.heroku.com/articles/github-integration#automatic-deploys
 [ticket #71]: https://github.com/alphagov/govuk-prototype-kit-docs/issues/71
-[govuk-prototype-kit-docs pipeline]: https://dashboard.heroku.com/pipelines/f0879aaf-21f5-4430-a1d5-7adc4740a066
+
+## Pull Request previews
+
+Previews of Pull Requests are automatically published to a URL which has the
+prefix `deploy-preview` followed by the identifier number of the pull request.
+
+For example, pull request #137 would be deployed to
+`deploy-preview-137--prototype-kit-docs.netlify.app`.
+
+The Netlify bot should comment on each PR shortly after building with a link to
+the preview.