In the "Push users" section you get insights about the push notification users that subscribed to receive your notifications. the insights include information about their country, platform, browser, supported languages, first and last session date.
You can use this information in order to create custom segments - groups of users based on country, language, browser, last session to be used to send push notification campaigns to specific segment of users.
You can manage the segments from Manual Campaigns or AI Push sections in the left hand menu.