The name of the transition is the one that needs the CSS class:

.list-move {
  transition: transform 1.5s;
}

(with name="list")

Please check the documentation about transitions for more info

@posva I see, so there is no way to change duration dynamically?

@posva
Your answer unfortunately doesn't answer the dynamically part of the OP's question.

Since #4857, the duration of a transition can be set (dynamically) via its props. In a transition-groups however this prop does not exist.

Is there a reason for that - or would that be something for a PR?

If not, what ways do you see to dynamically define styles for a transition-group? I obviously don't want to create a class for each duration.

Any solutions?