Glossary does not define "extended slicing"

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2017-12-12.13:03:53.588>
labels = ['type-feature', 'docs']
title = 'Glossary does not define "extended slicing"'
updated_at = <Date 2017-12-12.13:03:53.588>
user = 'https://github.com/stevendaprano'

bugs.python.org fields:

activity = <Date 2017-12-12.13:03:53.588>
actor = 'steven.daprano'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2017-12-12.13:03:53.588>
creator = 'steven.daprano'
dependencies = []
files = []
hgrepos = []
issue_num = 32289
keywords = []
message_count = 1.0
messages = ['308125']
nosy_count = 3.0
nosy_names = ['steven.daprano', 'docs@python', 'Massimiliano Culpo']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue32289'
versions = []