Header Files

• Chromium Source Code
• header file is a file containing C declarations and macro definitions (see Macros) to be shared between several source files. You request the use of a header file in your program by including it, with the C preprocessing directive ‘#include’.
• gcc_gnu_org

https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html#:~:text=A%20header%20file%20is%20a,Header%20files%20serve%20two%20purposes.