Current path
First-party packages are built, pinned and installed through a trusted catalog in the browser runtime.
Developers / App platform
ViXL Apps are packaged show capabilities with defined roles, state and lifecycle, not just visual web pages.

The idea
A curated first-party App path is available in the browser runtime. Apps can be content, interactive, control, information, processing, transition, output or utility/data capabilities; a package may eventually contain multiple endpoints.
First-party packages are built, pinned and installed through a trusted catalog in the browser runtime.
A prepared target must load, warm and report READY before GO when required.
Shared state, multi-endpoint Apps and additional host roles are forward contracts, not general public publishing features.
Where it stands
Open marketplace publishing, arbitrary third-party installation, and a public SDK support program are not yet available. The App Library shows the current curated set.