What access do you need to fix a frontend bug?

To start, just the URL of the broken page, a screenshot or screen-recording, and the device/browser it breaks on, we can often diagnose the root cause from that alone. To ship the fix we need access to the theme files (Git, SFTP or admin), or a staging environment. For Magento we also like read access to the CLI so we can run the static-content deploy and cache clears properly.