Do you have any idea of the
modification ?
Not without further exploratory surgery on the patient - but what I see reminds me of the old Emperor TS-5010 had similar "Battery backup" - or Pacemaker - keep alive issues - so this looks to be some kind of mod for the original "cap" that was keeping the Chip alive as well as the chips own non-volatile memory (NVRAM) failed they somehow rigged this to keep the memory alive so the radio was still keeping last channel and CB mode operational.
Best Guess - your results may vary - Not Responsible for Articles Left in Clothing...