/usr/include/postgres-xc/server/executor/ is in postgres-xc-server-dev 1.1-2ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/postgres-xc/server/executor/execdebug.h
/usr/include/postgres-xc/server/executor/execdesc.h
/usr/include/postgres-xc/server/executor/executor.h
/usr/include/postgres-xc/server/executor/functions.h
/usr/include/postgres-xc/server/executor/hashjoin.h
/usr/include/postgres-xc/server/executor/instrument.h
/usr/include/postgres-xc/server/executor/nodeAgg.h
/usr/include/postgres-xc/server/executor/nodeAppend.h
/usr/include/postgres-xc/server/executor/nodeBitmapAnd.h
/usr/include/postgres-xc/server/executor/nodeBitmapHeapscan.h
/usr/include/postgres-xc/server/executor/nodeBitmapIndexscan.h
/usr/include/postgres-xc/server/executor/nodeBitmapOr.h
/usr/include/postgres-xc/server/executor/nodeCtescan.h
/usr/include/postgres-xc/server/executor/nodeForeignscan.h
/usr/include/postgres-xc/server/executor/nodeFunctionscan.h
/usr/include/postgres-xc/server/executor/nodeGroup.h
/usr/include/postgres-xc/server/executor/nodeHash.h
/usr/include/postgres-xc/server/executor/nodeHashjoin.h
/usr/include/postgres-xc/server/executor/nodeIndexonlyscan.h
/usr/include/postgres-xc/server/executor/nodeIndexscan.h
/usr/include/postgres-xc/server/executor/nodeLimit.h
/usr/include/postgres-xc/server/executor/nodeLockRows.h
/usr/include/postgres-xc/server/executor/nodeMaterial.h
/usr/include/postgres-xc/server/executor/nodeMergeAppend.h
/usr/include/postgres-xc/server/executor/nodeMergejoin.h
/usr/include/postgres-xc/server/executor/nodeModifyTable.h
/usr/include/postgres-xc/server/executor/nodeNestloop.h
/usr/include/postgres-xc/server/executor/nodeRecursiveunion.h
/usr/include/postgres-xc/server/executor/nodeResult.h
/usr/include/postgres-xc/server/executor/nodeSeqscan.h
/usr/include/postgres-xc/server/executor/nodeSetOp.h
/usr/include/postgres-xc/server/executor/nodeSort.h
/usr/include/postgres-xc/server/executor/nodeSubplan.h
/usr/include/postgres-xc/server/executor/nodeSubqueryscan.h
/usr/include/postgres-xc/server/executor/nodeTidscan.h
/usr/include/postgres-xc/server/executor/nodeUnique.h
/usr/include/postgres-xc/server/executor/nodeValuesscan.h
/usr/include/postgres-xc/server/executor/nodeWindowAgg.h
/usr/include/postgres-xc/server/executor/nodeWorktablescan.h
/usr/include/postgres-xc/server/executor/spi.h
/usr/include/postgres-xc/server/executor/spi_priv.h
/usr/include/postgres-xc/server/executor/tstoreReceiver.h
/usr/include/postgres-xc/server/executor/tuptable.h