Why would files be "hidden"?

[MarieMeyer]

I just noticed this little message below the Filter panel in the lower right. Why would some items be "hidden"?

[Stephen_A_Marsh · Accepted solution]

They could be invisible system files, they could be XMP sidecar files etc. There are pros/cons for showing or hiding them, often dependent on the task at hand. Use the View menu > Show Hidden Files command to make them visible.