OAT

OAT files aimed to replace ODEX in the newer ART environment. To begin with, the file extensions shouldn't be trusted when dealing with Android executables. In particular, on recent Android systems, files with the .dex, .odex and .oat extensions may actually implement the OAT format. It is not very well-documented and varies for different versions of Android, but the most important thing here is that the result data is wrapped in ELF shared objects. Starting from Android Oreo, it doesn't store DEX code, leaving it to VDEX files, and is used mainly to store mapping information and the native code.