New Confluence Space migration test : how to use option Prefixed macros?

One of the options,
Prefixed macros The unknown macros for which the name should be prefixed. java.util.Set has caught my eye.
In a previous test we have met with the following Confluence Macros not recognized by XWiki, even with Pro Macros installed as a test period:

[livesearch]
[contentbylabel]
[popular-labels]
[time]
[task-list]
[jira]
[office]

I have two questions : how can this Prefixed macros option field can help to the success of the migration?
How should the syntax of the list look like in the field to complete?
Would it be separated by spaces ? Or by commas?
ie:
livesearch contentbylabel time… ?

It cannot really help much to “the success of the migration”, the only point of this option is to indicate which unknown confluence macros should be prefixed to avoid conflicting with existing ones with the same name but a different behavior/parameters.

Any of those works.

@tmortagne thank you very much.