Dota 2 users believe they have stumbled on the foundations of a brand new Source engine from Valve.
The firm has released a number of new workshop tools for the popular MOBA, and modder RoyAwesome claims their filenames suggest the game is being migrated to a new engine, according to VG247.
"Everything in this package is a new game," he posted on Reddit. "It's all the Dota assets and core ported over to Source 2. Valve just soft launched the entire Source 2 engine."
He points to all the files that would usually share a name with Source, each of which now have a '2' in the filename – examples including engine2.dll, vconsole2.exe. The game now also asks for .vmap files, referring to .vmf as "(Source 1.0)".
In Valve's release notes for the new workshop tools, the firm warned that they required powerful systems.
"This is a developer focused release and currently has high system requirements which means not everyone will be able to run the tools," the firm wrote.
Commence inevitable Half-Life 3 speculations… wait for it… now.