Wut?
Please. Just tell the user what’s wrong (if anything) and what to do in just a few words. If nothing is required to be done (which seems to be the case here as indicated by the word “Warning”) then don’t show a dialog box.
I foresee thousands of Unity developers getting used to clicking Ok for months on end because no one bothers to read these instructions (aka “big blob of bla”), let alone understand what needs to be done here, or whether - whatever it might be - actually needs anything done to said whatever.
And how would anyone even know whether UnityPackageManager folder is still needed? That assumes one actually knows about how Unity manages packages internally. It’s not something a lot of devs bother with.
Surely there’s a better solution to this … perhaps offer a readable warning and quick-fix functionality in the PackageManager GUI?