On Commons, when a user clicks on a wikilink [[Special:UserLogout]] (URL), they are presented with the following page (using English and Russian just as examples—all languages are affected):
|English||Submit||Log out||Log out|
|Russian||Отправить||Завершить сеанс работы||Выйти из системы|
While [[Special:UserLogout]] is technically an HTML form, there is nothing to "submit". The text on the button should probably be improved.
There is already suitable text in the localized strings, namely text of the string with key "tooltip-pt-logout" (Russian "Завершить сеанс работы")—"log out" here is a verb, as opposed to "userlogout" (Russian "Завершение сеанса"), where it is a noun. Obviously, a new localization key is required. Similar wording is currently used in localizable strings "logouttext" (Russian) and "session_fail_preview_html" (Russian).
The second suggestion in the table is based on the current wording of localizable strings "userlogout-continue" (Russian), (three in a row) "logout-failed", "cannotlogoutnow-title", and "cannotlogoutnow-text" (Russian).