I tried to create a file or folder object with a slash (colon) in its name in Illustrator CC2020, but I couldn't.
Also, I was not able to get the file object from PlacedItem.
The same thing happens with AppleScript.

In Photoshop CC2020 and InDesign CC2020,I was able to create.

NG Case(JSX)

[File location] desktop > 2020/01 > 01/01Image01.jpg ==> [Full path] /Users/***/desktop/2020:01/01:01Image.jpg

var fObj = File('/Users/***/desktop/2020:01/01:01_Image.jpg'); ==> invalid object
fObj.exists ==> false
fObj.name ==> none