If you mean the yellow "Preview Packages in Use" text, then it means that you have preview packages installed. https://docs.unity3d.com/Manual/pack-preview.html
Device Simulator is a preview package, indicated by the icon and having the -preview prefix in the version number.
Ok I can fix it now! by set it to show all packages first and I will see some package has a preview and then I remove it and that yellow text gone..