> `data-qa-*` data attributes and CSS classes starting with `qa-` are used solely for the purpose of QA and testing.
> By defining these, we add **testability** to the application.
>
> When defining a data attribute like: `qa_selector: 'labels_block'`, it should match the element definition: `element :labels_block`. We use a [sanity test](https://gitlab.com/gitlab-org/gitlab-foss/tree/master/qa/qa/page#how-did-we-solve-fragile-tests-problem) to check that defined elements have their respective selectors in the specified views.
> When defining a data attribute like: `qa_selector: 'labels_block'`, it should match the element definition: `element :labels_block`. We use a [sanity test](https://gitlab.com/gitlab-org/gitlab-foss/tree/master/doc/development/testing_guide/end_to_end/page_objects.md#how-did-we-solve-fragile-tests-problem) to check that defined elements have their respective selectors in the specified views.