Q:

Standard Practice for including custom library in examples folder

I have created my custom library with examples folder in them. The main header file is ABC_Node.h. I am referring the structure of Adafruit libraries for Arduino and in some repos under the examples folder I found a conflict for the inclusion of their header files.
Example
in some repos. they use double quotes ("") for including their header files e.g. #include "Adafruit_SHT31.h"
SHT31test.ino
on the contrary, in their BNO055 Arduino library they use brackets (<>) #include <Adafruit_BNO055.h> BNO055 Bunny sketch
I locally tested my library on the IDE and I have examples in which my library is in #include "ABC_Node.h" and it compiles without a problem.
Soon I wish to make the repository public and want to know if there is a standard practice for including header files for examples.

A:

You can use either. There is no "standard".
When using a raw C compiler there is a difference between the two as regards the order in which directories are searched for files to include, but with the Arduino that is completely irrelevant, so either can be used.
Personally I use <...> for libraries and "..." for header files that form part of the sketch.  It makes for easier identification of which is which, and conforms to the C standard of <...> for system-installed headers, and "..." for local headers.

