The pgm_read_byte_near() is a macro that reads a byte of data stored in a specified address(PROGMEM area).
The pgm_read_byte_near() is defined in hardware/tools/avr/avr/include/avr/pgmspace.h as below.
The input is address_short and the macro converts the address_short to uint16_t, then calls __LPM() macro.
Arduino 1.8.13/avr-gcc 7.3.0-atmel3.6.1-arduino
June 19, 2020