Currently, the Pipeline Multibranch plugin does not allow for remote triggering of jobs (or at least, not with an authorization token). It would be a very useful feature to have.
In my particular use case, while I run my own Jenkins server, I use Appveyor to perform windows builds. I'd like Appveyor to trigger my multibranch job so that it would download and process any artifacts from appveyor. As far as I can tell, the only reliable way to do this is to have multiple jobs.
With this feature in place, I can use the Generic Webhook Trigger plugin that supports passing an authorization token in headers instead of a query parameter