BlueALSA is a Bluetooth audio ALSA backend for Linux systems that integrates with BlueZ to provide A2DP, HFP/HSP, ASHA, and BLE-MIDI profiles. It operates as a daemon (bluealsad) managing Bluetooth connections and exposing audio streams via ALSA PCM plugins and D-Bus interfaces. The architecture is modular, separating transport management, codec handling, D-Bus communication, and ALSA plugin layers. Key entry points include the daemon (src/main.c), ALSA PCM plugin (src/asound/bluealsa-pcm.c), ALSA mixer plugin (src/asound/bluealsa-ctl.c), and control utility (src/bluealsactl/main.c). Data flows from ALSA applications through the PCM plugin to Bluetooth transports, with control signaling via D-Bus. External dependencies include BlueZ, ALSA, GLib, and various codec libraries (SBC, aptX, LDAC, etc.).