The description of the key is taken from the official Apple documentation - https://developer.apple.com/documentation/bundleresources/information_property_list/minimumosversion.

"MinimumOSVersion (String - iOS). When you build an iOS app, Xcode uses the iOS Deployment Target setting of the project to set the value for the MinimumOSVersion key. Do not specify this key yourself in the Info.plist file.".

When building via Qbs, the key does not appear in the plist, which leads to an application deployment error in the AppStore. The error result is attached to the issue.
The equivalent key for macOS, LSMinimumSystemVersion, is set by Qbs automatically and gets into the plist