From https://www.mediawiki.org/wiki/Topic:Vidtloktojlxxfrp

Article descriptions often don't follow the typographic norms. They add capitalisation (norm is not to capitalise) and punctuation (shouldn't be there) which creates extra work for the communities, make them less happy about the tool and makes it more difficult for newcomers to contribute in a good way. They add initial capital letters or ending punctuation which should rarely be the case. Suggestion from the thread:

"if the suggestion ends with a punctuation (or start with an uppercase), remove the punctuation, except for a whitelist of the few exception where the punctuation is ok (there is almost no exception for punctuation, maybe a lot and tricky ones for uppercase...)."