I was able to reproduce this. If after downloading the zip file from github I assume you just double clicked the downloaded zip file and opened ubitx_20.ino by double clicking it too. Windows just extracted this file into a temp directory. In your case into:
C:\Users\mop\AppData\Local\Temp\Temp1_ubitx-master (5).zip\ubitx-master\ubitx_20
But only this file and not the other ones. To fix the problem just go to the Download directory where Windows saved the zip file and unzip or extract whatever command you have available with a right click on the zip file. From here you can move it to a more convenient place, but you could also try from the newly created directory in your download Folder.
When you now double click ubitx_20.ino, the Arduino IDE should now show ?all ino files in separate tabs and compile should work.
Good luck!
Armin, DJ2AG
