ne's manual

4.12.3: Exec

executes it. It is never registered while recording a macro (but the command you type is).

This command is mainly useful for key bindings, menu configurations, and in manually programmed macros.

Note that if the command you specify does not appear in ne's internal tables, it is considered to be a macro name. See Macro.

4.12.4: Flash

Same comments apply. See Beep.