Identifying & modifying progressive coefficient factors

Out of the box, taskwarrior comes with some progressive coefficient factors.
For example, those associated to number of tags/annotations:

- 0.8 for 1 tag or annotation
- 0.9 for 2 tags or annotations
- 1 for 3+ tags or annotations

Configuration doesn't detail them explicitely. One can only read their max value:

> urgency.annotations.coefficient 1.0
> urgency.tags.coefficient 1.0

So please:

- where can one distinguish those special factors from the non-progressive ones?
- how can one modify their thresholds?