For index based settings, "*" can be used as a wildcard character in the idx attribute. When the "*" is used, the same value and attributes will apply to that setting for all indexes.

The referred_by_brackets settings for 1 to 12  indexes are all set to "on".

<?xml version="1.0" encoding="utf-8" ?>
<settings>
    <phone-settings>
        <referred_by_brackets idx="*">on</referred_by_brackets>
    </phone-settings>
</settings>

All fkey (index 1 to 104) are assigned as context="active", label="" and line as the feature type.

<?xml version="1.0" encoding="utf-8" ?>
<settings>
    <functionKeys>
        <fkey idx="*" context="active" label="">line</fkey>
    </functionKeys>
</settings>