Lithium Pro

Lithium Pro appears to be a license app for the free Lithium reading app, rather than a standalone books app. Based on the metadata, its main purpose is to unlock Pro features inside Lithium after both apps are installed on the same Android phone. That means people would typically use it when they want extra customization or account-based syncing in the reading app they already use.

The listed Pro features suggest it is commonly used for reading-app personalization and data continuity. It may let users back up and sync app data across devices with a Google Drive account, while noting that the books themselves are not backed up or synced. It also appears to add theme controls such as page background, text, and link colors, plus additional highlight colors. Since there are no permissions listed, the app metadata does not indicate any special device access requirements beyond normal app use.