philchute.com/games/enemy territory

Enemy Territory was developed by Splash Damage as a Return to Castle Wolfenstien multiplayer expansion, but did not receive a retail release and was released as freeware in 2003, and later the code was released as open source.
The World War 2 gameplay features five classes: medic, engineer, soldier, field ops, and covert ops.
Enemy Territory: Legacy is a fully compatible client and server update to Enemy Territory.
Enemy Territory maintains active pubs with 22v22 gameplay nightly, also pickups, scrims, and tournaments organized on discord.
Youtube video: A Casual Movie
Youtube video: Oldschool Superstars
Youtube video: Wolfenstein Enemy Territory - Greatest Moments
Youtube video: ET 3on3 World Championship '15 [wings] by NgN
Youtube video: ET Spring Cup 2021 Group Stage Highlights [4k|60fps]
Youtube video: Enemy Territory: Legacy Trailer
Enemy Territory: Legacy website
Enemy Territory: Legacy discord
ET: Legacy Competitive discord
List of current games

In 2021 a community made replacement singleplayer/coop campaign was released as a Return to Castle Wolfenstien mod for PC, PSvita, and Quest VR headsets.
Youtube video: Wolfenstien: Enemy Territory Singleplayer - Official Launch Trailer
Enemy Territory Singleplayer & Co-op Downloads from modDB
Enemy Territory Singleplayer on Steam Workshop
Enemy Territory Co-op on Steam Workshop

In 2022 the original Enemy Territory client received a release on Steam. Enemy Territory on Steam
Youtube video: How to play ET: Legacy with ET Steam release