Following on from the call... Does this sound even better? (mapping
from the JVM for comparison):

The JVM is a specification of a virtual machine that runs Java
bytecode. It is implemented by a Java Runtime Environment, such as
OpenJDK, which includes an interpreter and a JIT compiler.

The BPF VM (BVM?) is a specification of a virtual machine that runs
BPF instructions (defined in filter.h, etc). It is implemented by the
Linux kernel BPF runtime, which includes an interpreter and a JIT
compiler. Most of the work for the past 5 years has been developing
the BPF runtime.