doc: experimental flag for global accessible APIs
Explicitly document that adding an API to the global scope requires
semver-major label. Waiving the semver-major requires a regular
TSC consensus process.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Explicitly document that adding an API to the global scope requires
semver-major label. Waiving the semver-major requires a regular
TSC consensus process.