<!--IssueSummary start--> <details> <summary> Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards. </summary> - [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=461891) </details> <!--IssueSummary end--> As part of the [acceptance criteria for Rapid Diffs](https://docs.gitlab.com/ee/architecture/blueprints/rapid_diffs/#acceptance-criteria) we need a way to isolate the application from the rest of the GitLab product. Criteria 3 and 4 both set very low limits for bytes to load, which would be hard to tune in the noise of a typical page load (approximately 3MB on production). Criteria 6 _requires_ this isolation as a matter of fact. Some guidelines: - When the page finishes loading, the browser network tab should look something like this: <img src="/uploads/588fe1cbe5237bdcfb456829f47fc054/image.png" width="400px" /> - Note that the `favicon` load is initiated automatically by the browser. - We must be able to add arbitrary CSS and JavaScript to this page - This must skip a compilation step (e.g. Webpack/Vite), which would add a huge amount of weight and bloat to the compiled file - There needs to be a location (e.g. some kind of `/public` folder) where we can drop test files that can be loaded directly by the native browser module loader. - We must be able to **opt back in** to some add-ons arbitrarily. - For example: - we may want to test with adding the standard GitLab authentication to the page - we may want to test re-adding the global stylesheet (e.g. `gitlab-ui` to the page) - etc. <!-- template sourced from https://gitlab.com/gitlab-org/gitlab/-/blob/master/.gitlab/issue_templates/Default.md -->