package (usually line 2) in /android/app/src/main/AndroidManifest.xml
applicationId (usually line 90) in defaultConfig section of /android/app/build.gradl
windowsでandroid向けbuildをしてて以下のエラーが出た場合
Error: Command failed: gradlew.bat app:installDebug -PreactNativeDevServerPort=8081
が出た場合
C:\Projects\myproject\Android>gradle