which shows the stability of various Backstage components has been added. Stability is communicated with a number, with higher numbers inferring increased stability.
For example, you should expect frequent breaking changes if you use the catalog-client package because it has a stability index of 0.
The core package, on the other hand, has a stability index of 2. Thus, you can expect a short deprecation period before breaking changes occur.
The Backstage team is laser focussed on stability and reliability at the moment and this is part of that effort.