Using Godot Version is 3.2.1 stable.
Ok, so after some testing I'm fairly sure this is a bug and not a feature. Though it seems to stem from my local system.
For one it exists in multiple projects both new and old. Secondly when I tried to use an older version of Godot (3.2) the line is still there. Third, I re-downloaded 3.2.1 and directly ran it from the .zip (which would have extracted it first to the temp folder) and wouldn't you guess, it's also there.
So yeah, looks like whatever this is from, it's local. Don't know how I can replicate it for others.
Separate topic, @Megalomaniak I finished registration hours ago and still can't post any images. The only notification I get is "Server responded with 0 code"