When players log in or log out, reannounce the cumulative list of online players. This is particularly useful for szutil_chatsocket connections to external chat bridges, where no command is provided for getting the list of online players.
Player lists are only sent if either a certain amount of time has passed, or a certain number of public chat lines, since the last announcement (configurable) to prevent a ton of noise on busy servers.
The maximum number of names listed is configurable; beyond that limit, a random sample of players will be shown, and "(# more)" displayed at the end of the list.