org.slf4j

Nothing outside the APK knows this package by name - an in-house module, or a private SDK. What follows is what the code itself says.

In 25% of apps checked

What it contains37

Classes under this package in the newest build that carries it - Viber 29.1.1.0. Sub-packages: helpers (16), event (5), spi (4), impl (3).

Class
org.slf4j.ILoggerFactory
org.slf4j.IMarkerFactory
org.slf4j.Logger
org.slf4j.LoggerFactory
org.slf4j.MDC
org.slf4j.MDC$1
org.slf4j.MDC$MDCCloseable
org.slf4j.Marker
org.slf4j.MarkerFactory
org.slf4j.event.EventConstants
org.slf4j.event.EventRecodingLogger
org.slf4j.event.Level
org.slf4j.event.LoggingEvent
org.slf4j.event.SubstituteLoggingEvent
org.slf4j.helpers.BasicMDCAdapter
org.slf4j.helpers.BasicMDCAdapter$1
org.slf4j.helpers.BasicMarker
org.slf4j.helpers.BasicMarkerFactory
org.slf4j.helpers.FormattingTuple
org.slf4j.helpers.MarkerIgnoringBase
org.slf4j.helpers.MessageFormatter
org.slf4j.helpers.NOPLogger
org.slf4j.helpers.NOPLoggerFactory
org.slf4j.helpers.NOPMDCAdapter
org.slf4j.helpers.NamedLoggerBase
org.slf4j.helpers.SubstituteLogger
org.slf4j.helpers.SubstituteLoggerFactory
org.slf4j.helpers.Util
org.slf4j.helpers.Util$1
org.slf4j.helpers.Util$ClassContextSecurityManager
org.slf4j.impl.StaticLoggerBinder
org.slf4j.impl.StaticMDCBinder
org.slf4j.impl.StaticMarkerBinder
org.slf4j.spi.LocationAwareLogger
org.slf4j.spi.LoggerFactoryBinder
org.slf4j.spi.MDCAdapter
org.slf4j.spi.MarkerFactoryBinder

Each app's newest build, the most recently checked first. Where the version comes from is the file that states it.

App	App version	Classes
Viber com.viber.voip	29.1.1.0	37
Vita Mahjong com.vitastudio.mahjong	3.42.1	15
Block Blast! com.block.juggle	10.8.4	24
Zoho Mail com.zoho.mail	3.7.2	37
LinkedIn com.linkedin.android	4.1.1261	15
Reserved com.lppsa.app.reserved	3.13.0	55
Glovo com.glovo	2026.42.0	37
Duolingo com.duolingo	6.100.3	4
Tile Explorer com.oakever.tiletrip	2.3.0	15
Tapo com.tplink.iot	3.21.114	37
Shopify com.shopify.mobile	10.2640.0	37
EcoFlow com.ecoflow	6.17.4.14	35
and more