Documentation is unclear how "y*" and "y#" format units vary

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2017-06-10.18:16:12.023>
labels = ['type-bug', '3.7', 'docs']
title = 'Documentation is unclear how "y*" and "y#" format units vary'
updated_at = <Date 2017-06-17.03:18:44.489>
user = 'https://github.com/indygreg'

bugs.python.org fields:

activity = <Date 2017-06-17.03:18:44.489>
actor = 'martin.panter'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2017-06-10.18:16:12.023>
creator = 'indygreg'
dependencies = []
files = []
hgrepos = []
issue_num = 30625
keywords = []
message_count = 5.0
messages = ['295649', '296010', '296116', '296182', '296229']
nosy_count = 4.0
nosy_names = ['skrah', 'docs@python', 'martin.panter', 'indygreg']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'needs patch'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue30625'
versions = ['Python 3.5', 'Python 3.6', 'Python 3.7']