What Batt displays
By default, it shows:

the number of charge cycles
the charge status

However, if the android.permission.BATTERY_STATS permission is granted (which can be done from the app itself if you have Shizuku), it can also show:

the battery health
the battery manufacturing date
the battery first use date


Technical
The app is built using the traditional View-based system and Material 3 components. To get the BATTERY_STATS permission it uses the Shizuku API.

https://gitlab.com/narekt