The leads_retrieval permission allows your app to retrieve and read all information captured by a lead ads form associated with an ad created in Ads Manager or the Marketing API. You can use this permission to reach out to the people who followed up your lead ad form requesting more information. For example, an auto dealer reaching out to a potential customer (lead) that responded to their ad with quotes for a car. This permission can also be used by advertiser authorized CRM platforms to pull the lead data on behalf of the advertisers. These advertisers can then use the lead information to reach out to the user.