When you try to package a plugin on Mac in 4.23.0 Preview 1 there is no Shipping folder generated. This was verified to not happen in 4.22.3 (via Epic Launcher).
Found in 4.23.0 Preview 1 CL# 7236301
1. Open a new C++ project in UE 4.23.0 Preview.
2. Create a new blank plugin.
3. Package the new plugin.
4. Go to Intermediate/Build/Mac/UE4 folder for that plugin and check for the Shipping folder.
Result: No Shipping folder is created.
Expected: A Shipping folder with the appropriate files are created.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-77305 in the post.