/usr/include/mozjs-38/js/ is in libmozjs-38-dev 38.8.0~repack1-0ubuntu4.
This file is owned by root:root, with mode 0o755.
..
/usr/include/mozjs-38/js/CallArgs.h
/usr/include/mozjs-38/js/CallNonGenericMethod.h
/usr/include/mozjs-38/js/CharacterEncoding.h
/usr/include/mozjs-38/js/Class.h
/usr/include/mozjs-38/js/Conversions.h
/usr/include/mozjs-38/js/Date.h
/usr/include/mozjs-38/js/Debug.h
/usr/include/mozjs-38/js/GCAPI.h
/usr/include/mozjs-38/js/HashTable.h
/usr/include/mozjs-38/js/HeapAPI.h
/usr/include/mozjs-38/js/Id.h
/usr/include/mozjs-38/js/LegacyIntTypes.h
/usr/include/mozjs-38/js/MemoryMetrics.h
/usr/include/mozjs-38/js/Principals.h
/usr/include/mozjs-38/js/ProfilingFrameIterator.h
/usr/include/mozjs-38/js/ProfilingStack.h
/usr/include/mozjs-38/js/Proxy.h
/usr/include/mozjs-38/js/RequiredDefines.h
/usr/include/mozjs-38/js/RootingAPI.h
/usr/include/mozjs-38/js/SliceBudget.h
/usr/include/mozjs-38/js/StructuredClone.h
/usr/include/mozjs-38/js/TracingAPI.h
/usr/include/mozjs-38/js/TrackedOptimizationInfo.h
/usr/include/mozjs-38/js/TypeDecls.h
/usr/include/mozjs-38/js/UbiNode.h
/usr/include/mozjs-38/js/UbiNodeTraverse.h
/usr/include/mozjs-38/js/Utility.h
/usr/include/mozjs-38/js/Value.h
/usr/include/mozjs-38/js/Vector.h
/usr/include/mozjs-38/js/WeakMapPtr.h