Xcode 12 GM: Multiplatform Apps gone ?

The 12 GM release notes seem to feel differently:

Core Data
Resolved
When you create a multi-platform app project with Core Data, Xcode now correctly uses the name of the project for its data model. (67534882) (FB8483330)

Swift Packages
New Features
You can now declare conditions for a Swift package’s target dependencies, such as limiting the dependencies by platform. This gives you more flexibility to describe complex target dependencies that support multiple platforms. 

New Features
Documents can now be opened in their own tab, making it easy to quickly switch between files while maintaining the rest of Xcode’s configuration. Option-click or double-click to open a document in a tab. The tab bar appears when you have more than one document open, or you choose View > Always Show Tab Bar. (7954451)

I missed that section in the release notes, was searching for "Multiplatform" apps.

Anyway:

• When you want to create a new Project, only the Game template is now visible in the Multiplatform section. The Apps are gone.

• When you want to compile an existing Multiplatform app, I get errors, like

No such module 'UniformTypeIdentifiers'. UniformTypeIdentifiers is not available on OSX. Which seems strange. The iOS 14 Multi Document template now looks like the old Multiplatform template but does not work in Catalyst because of the missing UniformTypeIdentifiers support.

As long as your original question is solved, you may want to file bugs relating to follow-on issues, being sure to add your report number(s) to your thread for ref., thanks and good luck.

I have opened FB8697566 for this.

I was confused by this as well - I don't see the Multiplatform app option anymore either. Is it gone?

A useful bit of info from Apple Developer Support could inform developers if multiplatform SwiftUI projects (iOS and macOS, etc) can be created in any other final version after Xcode 12.0.1, or do we have to wait for the final Xcode 12.2 release? Juggling downloads only to discover bad glitches or omissions is eating a lot of time better spent on other projects. Thanks for any info you can share.