Learnings: What is an "Anglo-Saxon"?

It was once common in academia to group these peoples under the umbrella term "Anglo-Saxons". Now, many prefer to name tribes based on where they lived, like West Saxons, Mercians, etc.
The term "Anglo-Saxon" is flawed; it creates the illusion that there was some sense of common ethnicity between the Germanic migrants where that wasn't necessarily the case.
This map represents the early medieval isle of Britain. Each coloured area corresponds with a different group of peope.
In YELLOW: the southern part of the territory of the Scots and the Picts;
In BLUE: the lands inhabited by the Welsh;
In RED: the territories settled by Saxons, Angles, Jutes, etc.
Each crown represents a major kingdom, although there were at one time many more English-speaking kingdoms:
- Northumbria
- Mercia
- East Anglia
- Essex
- Kent
- Sussex
- Wessex