Pair it with the May 2018 L2 image for a complete virtual lab that mirrors real ISR G2 routers (ISR 4321-like behavior).
This filename points to a very specific Cisco IOS image for the platform, commonly used in emulation environments like EVE-NG or GNS3 . i86bi_linuxl3-adventerprisek9-m2_157_3_may_2018.bin