.CLIPPING File

File extension clipping is most likely only used on older Mac OS platform for the purposes of saving text data that were added to the Finder window via drag and drop method.

Finder uses textclipping file extension for the same purposes since Mac OS 9 and continues to do so in macOS.

How to open:

Any text editor should be capable of viewing .clipping files.

How to convert:

ClippingSticker utility can be used to export the .clipping files to common graphics formats including JPEG. This will basically make a picture of the text window.