The first version of Angular was known by most people as Angular 1; it later became known as AngularJS. It did not use semantic versioning. Most people actually still refer to it as Angular 1.

Then Angular came along and in 2016 it reached production readiness. Angular decided to adopt semantic versioning and this caused a bit of confusion in the developer community, especially when it was announced that there would be an Angular 4 and 5, and so on. Google, as well as the Google Developer Experts, started to explain to people that it wanted people to call the latest version of the framework Angular - just Angular. You can always argue on the wisdom of that decision, but the fact remains, the new Angular is using semantic versioning. This means Angular is the same platform as Angular 4, as well as Angular 11, and so on, if that ever comes out. Adopting semantic versioning means that you as a user of Angular can rely on things working the same way until Google decides to increase the major version. Even then it's up to you if you want to remain on the latest major version or want to upgrade your existing apps.