Plain simple modbus master / slave -demo-code

No example-code at all

No comments that would explain the parameters

The simple-master-comment says

well this is what all my computers have installed and I am familiar with
(ironic - no of course not!)

master-example shows all functions
This program use 8 modbus functions and shows how to use it in loop.

slave-code
This example shows how to use ModbusSlaveRTU object in pair with ModbusMemory object.

what is the ModBusMemory-Object ?? sounds like something extra = extra work an time to find out. master and slave-code seem not to match each other

This sketch creates a Modbus RTU Client and demonstrates
how to use various Modbus Client APIs.
This sketch creates a Modbus RTU Server and demonstrates
how to use various Modbus Server APIs.

Now what is a client and server in case of modbus?? I thought it is master/slave?
is it the same?
Do the demo-codes fit to eacher? Seems not to be so

This is all that the slaves demo-code contains

void loop() {
  mb.task();
  yield();
}

??? So again the situation of analysing the library itself
It is called ESP8266-modbusRTU - not very promising I am looking for non-ESP-modbus-code

the name says it ModbusRTUSlave
no code for a modbus-master included
Additionally the repo says

Warning

ModbusRTUSlave is currently undergoing a redesign. Things may not work, or may not be corretly documented.

Did you find another one? If yes please post the link.

Does anybody use his own microcontrollers
which means both modbus-master and modbus-slave