1. The jar1 Variant
JAR defines multiple protocol variants via the JarVariant typeclass. This
document describes jar1 — the latest variant, which extends the Gray Paper's
base protocol with a capability-based execution model (JAVM), a coinless
quota-based economy, variable validator sets, and single-pass gas metering.
Earlier variants (gp072\_full, gp072\_tiny) use the Gray Paper's original
flat-memory PVM model and balance-based token economy. They are preserved for
conformance testing but not documented here.