unable to find package Microsoft.NETCore.App.Runtime.browser-wasm

[CincySteve]

I am getting "unable to find package Microsoft.NETCore.App.Runtime.browser-wasm" when trying to Build an AspNetCore 5.0.0 Blazor Wasm app using VS Community 2019 v16.8.3 on Windows 10. I haven't tried to Build this app since early December, when it worked. I get the same error when I try to Build older backup copies of the app too. If memory serves, I upgraded VS from 16.8.2 to 16.8.3 since the successful Build. I have in recent days created a new AspNetCore 3.2.1 Blazor Wasm app using the same VS. It Builds and runs successfully.

This post indicates this package is not meant for direct consumption, but suggests doing an Install-Package. I tried that, but got an "unable to find package" error with Package Source set to "All" [see here]. The only specific system Package Source is "MS VS Offline Packages", which may not be right despite this being a client-only WASM app.

Any idea how to get out of this?