Steps

To set the Extension Rights when viewing a Page, for a specific Page:

1. View the Page.
2. Administer the Page.
3. Select "Users & Rights", and then select XWiki 18.2.0-rc-1+ "Extension Rights:Page & Children" or "Extension Rights:Page" from the dropdown, depending on your needs.

   

4. Select the "Groups" or the "Users" tab, depending on whom the right is for, then click the check box where the group or user meets the extension right: once to allow it, twice to deny it, and a third time to clear it and fall back to the default value.

FAQ

What is the difference between "Extension Rights:Page & Children" and "Extension Rights:Page" ?

The rights defined for "Extension Rights:Page & Children" will apply to current Page and to all its children, while "Extension Rights:Page" sets rights only for the current Page. XWiki <18.2.0-rc-1 There was only one entry "Extension Rights", where the rights could have been applied to the current Page only.

Can I set the Extension Rights globally for the whole wiki?

Yes, you can change the extension rights globally.