/usr/include/lexertl/ is in libpuma-dev 1:1.2-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/lexertl/bool.hpp
/usr/include/lexertl/char_traits.hpp
/usr/include/lexertl/compile_assert.hpp
/usr/include/lexertl/containers/
/usr/include/lexertl/containers/bitvector.hpp
/usr/include/lexertl/containers/ptr_list.hpp
/usr/include/lexertl/containers/ptr_map.hpp
/usr/include/lexertl/containers/ptr_stack.hpp
/usr/include/lexertl/containers/ptr_vector.hpp
/usr/include/lexertl/debug.hpp
/usr/include/lexertl/enums.hpp
/usr/include/lexertl/file_shared_iterator.hpp
/usr/include/lexertl/generate_cpp.hpp
/usr/include/lexertl/generator.hpp
/usr/include/lexertl/internals.hpp
/usr/include/lexertl/is_same.hpp
/usr/include/lexertl/licence_1_0.txt
/usr/include/lexertl/lookup.hpp
/usr/include/lexertl/old/
/usr/include/lexertl/old/string_token.hpp
/usr/include/lexertl/parser/
/usr/include/lexertl/parser/parser.hpp
/usr/include/lexertl/parser/tokeniser/
/usr/include/lexertl/parser/tokeniser/re_token.hpp
/usr/include/lexertl/parser/tokeniser/re_tokeniser.hpp
/usr/include/lexertl/parser/tokeniser/re_tokeniser_helper.hpp
/usr/include/lexertl/parser/tokeniser/re_tokeniser_state.hpp
/usr/include/lexertl/parser/tree/
/usr/include/lexertl/parser/tree/end_node.hpp
/usr/include/lexertl/parser/tree/iteration_node.hpp
/usr/include/lexertl/parser/tree/leaf_node.hpp
/usr/include/lexertl/parser/tree/node.hpp
/usr/include/lexertl/parser/tree/selection_node.hpp
/usr/include/lexertl/parser/tree/sequence_node.hpp
/usr/include/lexertl/partition/
/usr/include/lexertl/partition/charset.hpp
/usr/include/lexertl/partition/equivset.hpp
/usr/include/lexertl/rules.hpp
/usr/include/lexertl/runtime_error.hpp
/usr/include/lexertl/size_t.hpp
/usr/include/lexertl/sm_traits.hpp
/usr/include/lexertl/state_machine.hpp
/usr/include/lexertl/string_token.hpp
/usr/include/lexertl/utf_iterators.hpp