Loop through all items in all lists in the site, check if column(Target Audiences)value equals ContosoHRAud to find where ContosoHRAud is being applied in all items.
For web parts, iterate through all web parts in all pages in the site,check the web part property "AuthorizationFilter" values are equals ContosoHRAud to find where ContosoHRAud is being applied in all web parts.
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