I have a Nikon D3300. It has a full-auto mode, various degrees of semi-auto, and a full-manual mode. It also has a box of what you might call "application-specific" modes, for example "landscape", "portrait", "sport", "macro", etc.

Is there any documentation about exactly what these modes do?

Some of them are obvious. "Sport" mode, for example, presumably prioritises a fast shutter speed. The documentation for "portrait" mode talks in vague terms about blurring the background to make the subject stand out — so, reading between the lines, it presumably prioritises a wide aperture. (But who knows? Maybe it also changes the white-balance or something?)

But what about, say, "landscape" mode? The documentation states that it turns the flash off. But what else does it do? Without knowing specifically what it does, it's difficult to know what it might actually be useful for. ("Landscapes" is somewhat vague. And who knows, maybe it's also suitable for tapestries or something?)

The "effects" menu houses a bunch of options like "oil painting" which are clearly post-processing effects. But what about "hi-key" and "lo-key"? Does that just change the exposure metering? Or does it actually post-process the image to alter the brightness curve or something?