/usr/include/mozjs-52/js/ is in libmozjs-52-dev 52.3.1-7fakesync1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/mozjs-52/js/CallArgs.h
/usr/include/mozjs-52/js/CallNonGenericMethod.h
/usr/include/mozjs-52/js/CharacterEncoding.h
/usr/include/mozjs-52/js/Class.h
/usr/include/mozjs-52/js/Conversions.h
/usr/include/mozjs-52/js/Date.h
/usr/include/mozjs-52/js/Debug.h
/usr/include/mozjs-52/js/GCAPI.h
/usr/include/mozjs-52/js/GCAnnotations.h
/usr/include/mozjs-52/js/GCHashTable.h
/usr/include/mozjs-52/js/GCPolicyAPI.h
/usr/include/mozjs-52/js/GCVariant.h
/usr/include/mozjs-52/js/GCVector.h
/usr/include/mozjs-52/js/HashTable.h
/usr/include/mozjs-52/js/HeapAPI.h
/usr/include/mozjs-52/js/Id.h
/usr/include/mozjs-52/js/Initialization.h
/usr/include/mozjs-52/js/LegacyIntTypes.h
/usr/include/mozjs-52/js/MemoryMetrics.h
/usr/include/mozjs-52/js/Principals.h
/usr/include/mozjs-52/js/ProfilingFrameIterator.h
/usr/include/mozjs-52/js/ProfilingStack.h
/usr/include/mozjs-52/js/Proxy.h
/usr/include/mozjs-52/js/Realm.h
/usr/include/mozjs-52/js/RequiredDefines.h
/usr/include/mozjs-52/js/RootingAPI.h
/usr/include/mozjs-52/js/SliceBudget.h
/usr/include/mozjs-52/js/StructuredClone.h
/usr/include/mozjs-52/js/SweepingAPI.h
/usr/include/mozjs-52/js/TraceKind.h
/usr/include/mozjs-52/js/TracingAPI.h
/usr/include/mozjs-52/js/TrackedOptimizationInfo.h
/usr/include/mozjs-52/js/TypeDecls.h
/usr/include/mozjs-52/js/UbiNode.h
/usr/include/mozjs-52/js/UbiNodeBreadthFirst.h
/usr/include/mozjs-52/js/UbiNodeCensus.h
/usr/include/mozjs-52/js/UbiNodeDominatorTree.h
/usr/include/mozjs-52/js/UbiNodePostOrder.h
/usr/include/mozjs-52/js/UbiNodeShortestPaths.h
/usr/include/mozjs-52/js/UniquePtr.h
/usr/include/mozjs-52/js/Utility.h
/usr/include/mozjs-52/js/Value.h
/usr/include/mozjs-52/js/Vector.h
/usr/include/mozjs-52/js/WeakMapPtr.h