-MO=Concise basics:

• The name of the opcode is followed by flags that are mostly opcode-specific. The exceptions are leading "v"oid, "s"calar and "l"ist, which indicate the context of the opcode.
• The letters/numbers in the first column are labels generated by B::Concise.
• A label of "-" denotes an unreachable opcode.
• A name starting with "ex-" denotes an unreachable opcode.
• -> is followed by the label of the next opcode in the program.
• The -exec option (-MO=Concise,-exec) shows the opcodes in the order they are executed, leaving out removed opcodes.