Build configurations in code is a more than useful feature for the programmer. Recently though I came in a situation in which I needed the same feature for the manifest editor. I was developing an application both for Android TV and Phone/Tablet and I needed a different "code" in manifest according to the version. This is not possible with the current B4A IDE so for the time being I just devided the two manifests with a REMed line of stars and I REM each time the different section for the different configuration - not a great solution but definitely a workaround. Build configurations in manifest would be a great feat to have.