Create a new project with "New project -> Prebuilt Project"

Select the firmware hex file

Select the PIC18LF2520 in the 8-bit PIC section

Go to "Window -> Target Memory View -> Program Memory" and click the "Read Device Memory" button. Verify it reads some bytes.

In the top menu, find the "Read Device Memory" button, click its drop-down arrow and select "Read Device Memory To File"