Can anyone please tell me the usage of .d files? I saw the below explanation in a blog

"The .d files are responsible for checking all file dependencies, i.e., which files need to be recompiled if one header has been changed."

The .d files given to me in the build to test have a set of .h files written in them. (eg; x.d files talks of some a.h and b.h).

Any information on .d files would be very helpful.