In the C++ Boost libraries, why is there a “.ipp” extension on some header files

Question

In the C++ Boost libraries, why is there a \".ipp\" extension on some header files?

It seems like they are header files included by the \".hpp\" file of the same n

Answer 1

I believe "ipp" stands from "implementation" file. i.e, they hold actually code (for inline functions & templates) rather than just declaration (which are in the header --.H or .HPP -- files)