Flent is a mature, actively maintained network testing tool designed primarily for bufferbloat detection. It wraps multiple simultaneous network performance tools (netperf, iperf, ping, fping, irtt) into a single coordinated test, aggregates time-series data, and produces publication-quality plots via matplotlib. The architecture is a Python CLI application with an optional Qt GUI, built around a modular system of test definitions (Python .conf files), pluggable runners, aggregators, combiners, and formatters. It supports batch execution for reproducible experiments, extensive metadata collection (kernel parameters, qdisc stats, WiFi stats), and multiple output formats (CSV, JSON, plots). While primarily an application, it has strong data collection and analysis characteristics, making it a hybrid tool for network performance research. The codebase is well-structured with clear separation of concerns, though it carries some legacy Python 2 compatibility shims and platform-specific Linux dependencies.