I'm getting the error "Cannot create Swift scratch context (couldn't create a ClangImporter)" when running a Swift project in XCode 12.3 on Catalina when I try to use the debugger. There is a resolution of this problem described at https://forums.raywenderlich.com/t/entering-debugger-in-swift-project-couldnt-create-a-clangimporter/130829 but I don't understand the fix of "removing zsh customisations in dotfiles". Can anyone explain what the files to change are and how they have to be changed? (I'm new to Mac development)

How can I create a simulator for an iPhone 6 (runninf iOS12.4) in Xcode 12.3? Entries in the Simulators list shown in Preferences->Components are all greyed out. The entries go up to iOS14.2. If I try to create a new Simulator by clicking + in Window->Devices and Simulators, Simulators tab, the only OS version available in the dropdown is iOS 14.3. If I try to download more Simulator runtimes I see the greyed out list shown in Preferences->Components.

When viewing total downloads for an App in App Store Connect App Analytics, the option to filter Total Downloads by version is greyed out when clicking Add Filter even though the app has had a version change 1 week ago as shown in the App Store Version history. The version option is greyed out when running App Store Connect from Windows (using Firefox) and from a Mac (using Safari)