The gdb/NEWS file documents this addition as:
** A new command, "rbreak" has been added to the Python API. This
command allows the setting of a large number of breakpoints via a
regex pattern in Python. See the manual for further details.
However, this is not a new *command*. This a new *function*.
The gdb-8.1-branch branch has been updated by Joel Brobecker <email@example.com>:
Author: Joel Brobecker <firstname.lastname@example.org>
Date: Fri Feb 9 16:04:38 2018 +0400
gdb/NEWS: Clarify the news entry for "rbreak" in GDB 8.1
* NEWS <Changes in GDB 8.1>: Clarify that "rbreak" is a new
Python function, rather than a new command.