Extend course presentation with own type



we want "extend" some standard H5P activities, for example we need to add our own content-type to course presentation. We don't want create a fork or something like that. So the question is, if there's any way we can extend the standard activities in H5P? At the moment the only way I see is forking it, but maybe there's also another better way because it's always hard to keep forks up to date.