.UEC File

The uec file extension is related to the UltraEdit, a text editing and source code editing program for OS X (macOS), Linux and Windows, developed by IDM Computer Solutions.

The uec file stores settings from UltraEdit.

How to open:

It doesn't seem these files are meant to be opened directly, they are settings.

How to convert:

Settings files are typically not meant to be converted to anything else.