BREAKPT -- "Break Point lexfile".  Adds BLIST, BREAK, and UNBREAK to
BASIC.

Size: 365 bytes.

Adds breakpoints to BASIC, a feature usually only found in low-level
languages like assembly language debuggers.

BREAK lets you specify any line number or numbers where the HP-71
should automatically PAUSE (same as inserting a PAUSE at that line of
code). Even works on ROM programs!  Primarily useful for debugging,
but also good for simple program control and for figuring out how
somebody else's program works.

UNBREAK clears all breakpoints set by BREAK.

BLIST lists all the current breakpoint line numbers.