/usr/lib/x86_64-linux-gnu/groonga/ is in libgroonga0 6.0.1-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/groonga/plugins/
/usr/lib/x86_64-linux-gnu/groonga/plugins/query_expanders/
/usr/lib/x86_64-linux-gnu/groonga/plugins/query_expanders/tsv.so
/usr/lib/x86_64-linux-gnu/groonga/plugins/ruby/
/usr/lib/x86_64-linux-gnu/groonga/plugins/ruby/eval.so
/usr/lib/x86_64-linux-gnu/groonga/plugins/ruby/load.so
/usr/lib/x86_64-linux-gnu/groonga/plugins/sharding/
/usr/lib/x86_64-linux-gnu/groonga/plugins/sharding.rb
/usr/lib/x86_64-linux-gnu/groonga/plugins/sharding/logical_count.rb
/usr/lib/x86_64-linux-gnu/groonga/plugins/sharding/logical_enumerator.rb
/usr/lib/x86_64-linux-gnu/groonga/plugins/sharding/logical_parameters.rb
/usr/lib/x86_64-linux-gnu/groonga/plugins/sharding/logical_range_filter.rb
/usr/lib/x86_64-linux-gnu/groonga/plugins/sharding/logical_select.rb
/usr/lib/x86_64-linux-gnu/groonga/plugins/sharding/logical_shard_list.rb
/usr/lib/x86_64-linux-gnu/groonga/plugins/sharding/logical_table_remove.rb
/usr/lib/x86_64-linux-gnu/groonga/plugins/sharding/parameters.rb
/usr/lib/x86_64-linux-gnu/groonga/plugins/sharding/range_expression_builder.rb
/usr/lib/x86_64-linux-gnu/groonga/plugins/table/
/usr/lib/x86_64-linux-gnu/groonga/plugins/table/table.so
/usr/lib/x86_64-linux-gnu/groonga/plugins/token_filters/
/usr/lib/x86_64-linux-gnu/groonga/plugins/token_filters/stop_word.so
/usr/lib/x86_64-linux-gnu/groonga/scripts/
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/accessor.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/backtrace_entry.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/command.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/command_line/
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/command_line/grndb.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/command_line_parser.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/context/
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/context.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/context/error_level.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/context/rc.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/database.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/error.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/eval_context.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/expression.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/expression_rewriter.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/expression_rewriters.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/expression_size_estimator.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/fixed_size_column.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/id.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/index_column.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/index_cursor.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/index_info.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/initialize/
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/initialize/post.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/initialize/pre.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/logger/
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/logger.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/logger/level.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/object.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/operator.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/plugin_loader.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/query_logger/
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/query_logger.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/query_logger/flag.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/record.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/require.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/scan_info.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/scan_info_builder.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/scan_info_data.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/scan_info_search_index.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/table.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/table_cursor.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/variable_size_column.rb
/usr/lib/x86_64-linux-gnu/groonga/scripts/ruby/writer.rb