I think this is the solution you are looking for: https://developer.apple.com/documentation/xcode/including-notes-for-testers-with-a-beta-release-of-your-app
Basically you have to create a text file in the following location: MyApp > TestFlight > WhatToTest.en-US.txt
*You can create various localized versions if you want the notes to be available in other languages by replacing the locale code in the filename.
To automate it, you will want to run a script in the ci_scripts/ci_post_clone.sh file that creates/updates that text file with your desired notes.
I don't think you will need to actually commit those changes since Xcode Cloud has already checked out your repository, but not 100% sure.
I haven't verified this all works yet, but I am about to start testing it out for our nightly QA builds by generating that file with the last 24hrs worth of commit messages.
I'll post my results here once I go through the whole flow though.
Topic:
Developer Tools & Services
SubTopic:
Xcode Cloud
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