Privacy

Kern keeps your notes and phone-use records on your device. It has no account or ads. Optional diagnostics use Firebase; paywalls and purchases use Google Play and Superwall.

Luna Maze publishes Kern and is responsible for the app practices described here. This policy explains the local features, optional diagnostics and purchase services.

What leaves your phone

This policy describes Android version 1.1 and later. Earlier versions may not include these services. Kern does not ask for your name, email, contacts or account. Private notes, pages, searches, notification content and records of which apps you use are not attached to analytics or paywall events.

Optional usage and diagnostics. Firebase Analytics and Crashlytics are off until you agree in Kern. You can decline without losing launcher features, and change your answer in Settings.
Paywalls and purchases. Superwall provides plan screens, purchase validation and subscription status through Google Play. These services operate separately from optional diagnostics.

Usage and diagnostics, only with your agreement

When enabled, Kern sends Firebase a fixed vocabulary of feature, tutorial, pause-outcome, preview and purchase-result events. These can include the feature category, subscription tier, preview day and product identifier. Firebase also processes installation identifiers, sessions, app/device versions, language and general location derived from the network address. Advertising ID collection and advertising personalization are disabled.

Crashlytics receives crash and diagnostic reports, including stack traces, installation identifiers and device/app state. Kern does not deliberately attach your private content. These identifiers distinguish installations; reports are not described as anonymous simply because Kern does not ask for your name. See Firebase privacy information.

Settings shows custom events handed to Firebase during the current session. This is not a delivery receipt or a complete list of SDK-generated events. Turning reports off stops future optional collection. Resetting local analytics creates a fresh local analytics identity and clears local state; it does not erase previously uploaded reports. Provider retention settings and policies apply to uploaded data. Contact us about access or deletion requests.

What stays on your phone

Kern stores the following in Android’s private app storage. It does not upload this content or detailed phone-use history to Firebase or Superwall. Exports you choose and Android’s own backup/restore settings are separate:

Your pages and notes.Everything you write, kept in Kern’s own storage on the phone.
Screen-time figures.How long the screen was on and which apps were in front, read from Android’s usage statistics with your permission and summarised for the day’s record.
Notification counts. Which app sent a notification, at what hour, and what became of it — opened, dismissed, or withdrawn by the app. Kern neverstores a notification’s title, its text or its sender.
Data usage figures. How many bytes each app moved, read from the same Android usage statistics.
Battery readings. Percentage, charge counter, temperature and voltage, sampled over time so that capacity and drain rates can be worked out.
Which apps you open, and when. Used to put the app you are likely to want at the top of the drawer, and to order search results. Kept as counts and times, and clearable in one tap from Settings.
Your settings and layout. Favourites, hidden apps, theme and the rest.

Uninstalling Kern removes the local app copy. Exported files remain wherever you saved them. Android may back up and restore app data according to your device and Google account settings; manage those backups in Android. You can export your pages or clear what Kern has learned from Settings.

Permissions, and exactly why

Access for the optional features below can be left off; Kern still works with those features unavailable. Network access is a standard Android permission used by the services described here and does not have a separate runtime prompt.

Network access. Google Play and Superwall use it for paywall delivery and purchase checks. Optional Firebase reports use it after your agreement. The launcher and private notes work offline.
Usage access.The day’s record, and the data-usage figures. Android will not report screen time to any app without it. Granted by hand in system settings.
Notification access. The notification shelf, and counting interruptions. Notifications are read in order to show and dismiss them, and to count them. Nothing about their content is stored and nothing is transmitted.
Display over other apps. Returning a blocked app to the home screen during a focus session. Used for nothing else.
Biometric or device credential. Unlocking a page or the inbox you have chosen to lock. Kern never sees your fingerprint or PIN; it asks Android whether you are you and receives a yes or a no.
Notifications. Sending you the charge alarm, if you turn it on.
Modify system settings. Optional, and grantable only over adb. Switching mobile data off on a schedule, if you choose to set that up. Used for nothing else.

Paywalls and payments

Google Play handles payment. Kern does not receive card details. Superwall processes installation identifiers, paywall interactions, device/app metadata, service diagnostics, loading/performance measurements, app/store region and network-derived region information, and Play purchase tokens or transaction details to load offers, restore access and keep subscription status current, including renewals and refunds. It can contact its service at startup to check configuration and existing access. Kern does not set an email or account identity in Superwall.

Purchase records are retained as needed to provide and verify access and handle subscription changes, subject to provider policies and applicable obligations. Uninstalling Kern or resetting optional analytics does not cancel a subscription or erase purchase records. Manage or cancel subscriptions in Google Play. See Google’s privacy policy and Superwall’s privacy policy.

Children

Kern is not directed at children. If you believe a child has supplied data to these services through Kern, contact us so we can investigate and assist.

Your choices and data deletion requests

Turn optional reports off or reset their local state in Settings. Export your pages before uninstalling if you want to keep them. To request access, correction or deletion of uploaded Kern information:

Email hello@lunamaze.com with the subject “Kern data request”. Say whether your request concerns usage/crash reports, paywall information or a purchase. No Kern account is required.
We will ask only for the information needed to find the relevant provider record. An email address alone does not identify a random installation. A Play order reference can help locate a purchase. Do not send private notes, card details or a Google password. Resetting local analytics first may make older analytics records impossible to locate.
We will explain which records can be located and deleted through the provider, complete supported deletion requests, and tell you which records must be kept and why. A deletion request does not cancel a subscription; cancel it separately in Google Play if desired.

Requests can cover identifiable Firebase usage/crash reports and associated installation identifiers, and Superwall paywall/customer records. Minimum transaction or entitlement records may need to remain while paid access must be restorable, for billing disputes, or to meet applicable obligations. Google Play retains its own transaction records under Google’s policies. Local notes and Android backups are managed separately as described above.

Retention and processing

Firebase starts removing Crashlytics crash reports and associated identifiers from live and backup systems after 90 days. Analytics uses the configured retention settings of the Analytics property; aggregated reports may remain. Purchase records follow the access and transaction-retention criteria above. We will explain any additional retention that applies when responding to a request. Kern does not sell personal information or use an advertising network. Providers process data on their infrastructure, which may be outside your country.

Changes

If this policy ever changes, the revised version will be posted here with a new date. Changes to optional diagnostics are explained in the app before consent. Purchase processing needed to provide paid access is described here.

Contact

Questions about privacy, or anything else: hello@lunamaze.com or lunamaze.dev@gmail.com.

For product, compatibility, feature and licence answers, read the Kern FAQ, or return to the Kern overview.

KERN · dev.lunamaze.kern · LAST UPDATED OCTOBER 18, 2026