The only external lib used is vortigont/LinkedList. It is already included into library manifest for Platformio, so should be picked up automatically.
It is possible to enable debugging output from the lib. To do so it is required to enable one (or both) of the following build-time flags:
PZEM_EDL_DEBUG - enables pzem-edl lib debug output using ESP32 Core debug logging facilities
CORE_DEBUG_LEVEL=ARDUHAL_LOG_LEVEL_DEBUG - must be set to raise ESP32 core debug level
or the same as
CORE_DEBUG_LEVEL=4
For Platformio project ini file this could be done in environment sections like this:
build_flags =
-DCORE_DEBUG_LEVEL=ARDUHAL_LOG_LEVEL_DEBUG
-DPZEM_EDL_DEBUG