personally i register this in code, and try to keep the package.manifest as simple as possible - especially with custom sections if you do any edit/add/etc stuff then the name/area of the section will be something you'll want in code,. makes it easier to apply security policies (for example if you want an Set of ApiController methods only to be available to people who can see a section - then the section / policy stuff has to be in c# code). having said that - some of that might be more nuanced/advanced so if your not to concerned with that, package.manifest is simpler 😉 .