You can force the HUD to use a manually specified name for a player. This may be useful if a player's name is too long or uses unwanted characters. Note that this override will not apply to the kill feed, which will still show the user's original in-game name.
To use player name overrides, use the teams.playerNameOverrides option on the HUD config page at http://127.0.0.1:31982/config.
Provide a player's SteamID64, followed by a space, and the name you want to use for the player.
You can specify as many players as you want, separated by line breaks.
For example:
76561198067382161 Dr. Weissbrot
76561197961491680 tabseN
You can find SteamID64s by appending ?xml=1 to a user's Steam profile URL (e.g. https://steamcommunity.com/id/drweissbrot?xml=1, it's at the very top between the <steamID64> tags), or using SteamDB's Calculator (it's the value labeled SteamID, usually starting with 7656).
The first match will be used, i.e. if you have the same player listed twice, the second name will be ignored. If you want to temporarily override a player's name, it's a good idea to add that override to the very beginning.