Welcome to TVPaint Community forums !

OK, there's the timecode FX which allows me to render a timecode or framecount in a layer.

But recently I got a TVP scene from elsewhere where the frame counter only ran during playback, had no layer for itself, and the FX stack was empty. How did they do that, and where can I switch this on and off? Manual doesn't help here.

Windows > Animation > Preview Settings > Show TC may be what you are talking about?

Ha! That's it! Thx!