Extensions and tools have their own development status, independent of Git branch status, which refers to project repository layout and Qbs items.
Extensions and tools may have one of the following statuses.
Product is in very early stage of development.
Product is in early development phase and it may be only partially functional. Its API is a subject of heavy changes.
Product has reached a phase, where it is functional, but some features are still to be added and its API may be a subject of slight changes. Some products may spent indefinite amount of time in this phase ("perpetual beta").
Product is rich in features and its API is stable, but some desired functionality is still missing or product has not been tested enough.
Product is feature complete. All desired features have been implemented (which does not prevent one from providing new ones). Its API is stable. Additionaly product should be well-documented and well-tested (or other applicable measures assuring its quality have been taken).
Product is going to be removed or replaced by some other product at some point.
Product is being removed or replaced by some other product.
Product is unmaintained. Due to lack of maintenance it might stopped being operational. While still considered valuable modernizations are needed to make it operational again.