The related policy change was under discussion at Wikipedia:Requests for comment/RfC to adopt a default gender neutral style for policy, guidelines and help pages from 7 April to 7 May 2017. However, the discussion ended with a detailed no consensus summary, which you can find in the rightmost, boxed column.

The English Wikipedia community is committed to providing a welcoming environment. Unless there is a specific reasonable need to the contrary, policy, guideline and help pages are to be written in gender neutral language, refer to Wikipedia:Policies and guidelines § Content. The use of gendered pronouns and other language that makes assertions about gender should be avoided. The policy applies to the language of official policy, guideline and help pages. It does not apply to any talk pages or user discussion venues, even if their purpose is to provide help to users, and it does not attempt to regulate the language used in those venues by individual editors.

In practical terms, existing statements which rely on phrases such as "he or she" may be replaced by use of "they" in its modern singular form; however, to keep the context of the sentence may require a reordering of phrases, or a rewrite to remain clear. Where reasonable to do so, sentences should be rewritten to avoid unnecessary pronouns altogether.

Example from Wikipedia:Banning policy

"An e-mail appeal must specify the banned editor's Wikipedia username and any other usernames he or she has used to edit Wikipedia in the past two years."

• Avoid. This makes an unwarranted assumption that the editor is identifiable as male or female and can feel unwelcoming for non-binary readers and contributors.

"An e-mail appeal must specify the banned editor's Wikipedia username and any other usernames they have used to edit Wikipedia in the past two years."

• Better. This uses the "singular they" type of construction which, although it has a long history in English, is a construction that some native speakers find uncomfortable. Readers whose first language is not English may find such language more difficult to understand because of the apparent conflict between "Wikipedia username" (singular) and "they" (more often plural).

"Appeals by e-mail must specify your Wikipedia username and any other usernames you have used to edit Wikipedia in the past two years."

• Better. As this part of policy explains a procedure of how banned editors can appeal, and the only action that can be taken is by a banned editor, the section can be recast in the second person. This gives a direct readable style and avoids unnecessary gendered pronouns.

"An e-mail appeal must specify the banned editor's Wikipedia username and any other usernames used to edit Wikipedia in the past two years."

• Best. In many cases it is possible to recast the original sentence to avoid using pronouns entirely, without losing meaning.

• Singular they
• Wikipedia:Gender-neutral language
• Wikimedia Commons policy, Commons:Use of gender neutral language
• American Dialect Society (9 January 2016). "2015 Word of the Year is singular "they"". americandialect.org. Retrieved 6 April 2017.
• Easton, Lauren (24 March 2017). "Making a case for a singular 'they'". The Definitive Source. Associated Press. Retrieved 6 April 2017.
• England, Barrie. "Singular 'they'". Caxton. Summary from an experienced teacher of English as a foreign language.