Meaning of in all games since

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(in all games since ) - means available in Half-Life 2 and all valve games that were released afterwards

(in all games since ) - would mean all Valve games except Source SDK Base 2006 and earlier, aswell as mods based on previous version of Source.
(in all games since ) - ^[Todo]
(in all games since ) - introduced in which means it's currently also in all Valve games, except Left 4 Dead engine branch-derived (basically up to ) games/mods and Source 2009 or earlier.
(in all games since ) - Introduced in and also in .

(in ) - All Source 2013 branch games (, , and )
(in ) - Half-Life: Source, Half-Life 2, Half-Life 2: Lost Coast, Half-Life 2: Episode One, Half-Life 2: Episode Two and Portal and any mods based on it.
(in ) - Counter-Strike: Source, Half-Life 2: Deathmatch, Half-Life Deathmatch: Source, Day of Defeat: Source and Team Fortress 2 (all pre-2025) and any mods based on it.
(in ) - Counter-Strike: Source, Half-Life 2: Deathmatch, Half-Life Deathmatch: Source, Day of Defeat: Source and Team Fortress 2 (all post Feb 18, 2025 engine update) and any mods based on updated Source SDK Base 2013 - Multiplayer (2025).

Source games in the release order

Engine version in parentheses indicates current engine versions; several games have been upgraded to new engine versions from older versions over time

Confirm:correctness

Game	Starting branch	Current branch
Counter-Strike: Source	Source 2004	Team Fortress 2 branch
Half-Life: Source	Source 2004	Source 2013 Singleplayer
Half-Life 2	Source 2004	Source 2013 Singleplayer
Half-Life 2: Deathmatch	Source 2004	Team Fortress 2 branch
Day of Defeat: Source	Source 2004	Team Fortress 2 branch
Half-Life 2: Lost Coast	Source 2004	Source 2013 Singleplayer
Half-Life Deathmatch: Source	Source 2004	Team Fortress 2 branch
Half-Life 2: Episode One	Source 2006	Source 2013 Singleplayer
Half-Life 2: Episode Two	Source 2007	Source 2013 Singleplayer
Portal	Source 2007	Source 2013 Singleplayer; slightly older version than
Team Fortress 2	Source 2007	Team Fortress 2 branch
Left 4 Dead	Left 4 Dead engine branch	Left 4 Dead engine branch
Left 4 Dead 2	Left 4 Dead engine branch	Left 4 Dead engine branch
Alien Swarm	Alien Swarm engine branch	Alien Swarm engine branch
Portal 2	Portal 2 engine branch	Portal 2 engine branch
Counter-Strike: Global Offensive	CS:GO engine branch	CS:GO engine branch