jextract generates a .jar or a .jmod. No documentation (javadoc or some such) is available for the generated Java interfaces. User has to look at the C header file and map the corresponding calls. clang exposes (doc) comment introspection API ( https://clang.llvm.org/doxygen/group__CINDEX__COMMENT.html ). jdk.internal.clang module should expose Java internal APIs (for jextract) for comment introspection. jextract tool can then use this internal API to generate documentation.