(On windows) If I try to save over a file "t.exg" by double-clicking on the existing file "t.exg", I get prompted for confirmation on whether to overwrite.
If I type "t" in the file browser and press enter, it still appends ".exg" to that path and overwrites "t.exg", but it doesn't confirm first.
I don't know what happens on Mac/Linux in this case.