That's mentioned on the Wikipedia page, [1]. What isn't mentioned is that the game Wolfenstein: Enemy Territory [2] from 2003 also contains a map called Siwa Oasis.
Agreed, the title rang such a strong bell in my mind that I had to know if anyone else remembers this map and the game in general... The number of hours on that game laughing and having fun with regulars from all over Europe...
Definitely! I got banned from multiple servers for repeatedly shooting rifle grenades into the tunnel the attackers had to pass through. Good times! :D
What I liked was that the riflenades are so predictable that on some maps you learn just exactly at what wall to fire them. Having a field ops behind you giving you ammo and shooting grenades into a tunnel is a solid tactic :D
[1] https://en.wikipedia.org/wiki/Siwa_Oasis#In_popular_culture
[2] https://en.wikipedia.org/wiki/Wolfenstein:_Enemy_Territory