"Some users store their own, regularly used Behaviors on the 'Forge (marked as private)"
This used to be a common use case, but since 2.0, with the ability to export a behavior locally, this isn't an optimal way to use Forge. Likewise, with all of the pre-shipped behaviors included in 2.0 and up, a huge reason behind that was to take StencylForge out as a dependency and to eliminate the need for a user to discover those.