ESP-IDF V4.1 esp_event_handler_instance_t not found

For me that file reads

3.40100.200827

which is the PIO-internal version number, and it has meaning. As described in Find the mbed version which was used before a backup? - #4 by maxgerhardt this would decode as “Major (PIO) package revision 3, internal version 4.1.0, datecode 2020 August 27th.”.