According to SteamDB records, there used to be an empty Steam depot for the game. As I checked Internet Archive Wayback Machine, there wasn’t any Steam Store or Steam Community page but it is still interesting to see the empty depot is still there.
REA987 (REA987) #1
wolfETplayer (wolfETplayer) #2
I saw that as well. What a shame. Would be great if publisher contacted ETL team and put their source port on Steam.