Как СПО-way настроить Bluetooth-наушники на GuixSD (shepherd + bluez) ?

$ uname -a
Linux antelope 4.18.15-gnu #1 SMP 1 x86_64 GNU/Linux

# lsmod | grep bluetooth
bluetooth             540672  14 btrtl,btqca,btintel,hci_uart,btbcm,bnep,ath3k,btusb
ecdh_generic           24576  1 bluetooth

# rfkill list bluetooth
1: ideapad_bluetooth: Bluetooth
	Soft blocked: no
	Hard blocked: no

# herd status | grep bluetooth
 + bluetooth

# bluetoothctl
Agent registered
[bluetooth]# list
[bluetooth]# devices
No default controller available
[bluetooth]# 

# guix package -s bluetooth
name: bluez-alsa
version: 1.2.0
outputs: out
systems: x86_64-linux i686-linux armhf-linux aarch64-linux mips64el-linux
dependencies: alsa-lib@1.1.6 autoconf@2.69 automake@1.16.1 bluez@5.50
+ glib@2.56.0 libbsd@0.8.7 libtool@2.4.6 ncurses@6.1 ortp@0.27.0
+ pkg-config@0.29.2 sbc@1.3
location: gnu/packages/audio.scm:3232:2
homepage: https://github.com/Arkq/bluez-alsa
license: Expat
synopsis: Bluetooth ALSA backend  
description: This project is a rebirth of a direct integration between Bluez
+ and ALSA.  Since Bluez >= 5, the build-in integration has been removed in
+ favor of 3rd party audio applications.  From now on, Bluez acts as a
+ middleware between an audio application, which implements Bluetooth audio
+ profile, and a Bluetooth audio device.  BlueALSA registers all known Bluetooth
+ audio profiles in Bluez, so in theory every Bluetooth device (with audio
+ capabilities) can be connected.  In order to access the audio stream, one has
+ to connect to the ALSA PCM device called `bluealsa'.  The device is based on
+ the ALSA software PCM plugin.
relevance: 11

name: gnome-bluetooth
version: 3.20.1
outputs: out
systems: x86_64-linux i686-linux armhf-linux aarch64-linux mips64el-linux
dependencies: eudev@3.2.5 glib@2.56.0 gobject-introspection@1.56.0
+ gtk+@3.22.30 intltool@0.51.0 libcanberra@0.30 libnotify@0.7.7 libxml2@2.9.8
+ pkg-config@0.29.2
location: gnu/packages/gnome.scm:5457:2
homepage: https://wiki.gnome.org/Projects/GnomeBluetooth
license: LGPL 2.1+
synopsis: GNOME Bluetooth subsystem  
description: This package contains tools for managing and manipulating
+ Bluetooth devices using the GNOME desktop.
relevance: 9

name: sbc
version: 1.3
outputs: out
systems: x86_64-linux i686-linux armhf-linux aarch64-linux mips64el-linux
dependencies: libsndfile@1.0.28 pkg-config@0.29.2
location: gnu/packages/linux.scm:3103:2
homepage: https://www.kernel.org/pub/linux/bluetooth/
license: GPL 2+
synopsis: Bluetooth subband audio codec  
description: The SBC is a digital audio encoder and decoder used to transfer
+ data to Bluetooth audio output devices like headphones or loudspeakers.
relevance: 5

name: bluez
version: 5.50
outputs: out
systems: x86_64-linux i686-linux armhf-linux aarch64-linux mips64el-linux
dependencies: dbus@1.12.6 eudev@3.2.5 gettext-minimal@0.19.8.1 glib@2.56.0
+ libical@3.0.3 pkg-config@0.29.2 readline@7.0.3
location: gnu/packages/linux.scm:3126:2
homepage: http://www.bluez.org/
license: GPL 2+
synopsis: Linux Bluetooth protocol stack  
description: BlueZ provides support for the core Bluetooth layers and
+ protocols.  It is flexible, efficient and uses a modular implementation.
relevance: 5

name: bluez-qt
version: 5.49.0
outputs: out
systems: x86_64-linux i686-linux armhf-linux aarch64-linux
dependencies: dbus@1.12.6 extra-cmake-modules@5.49.0 qtbase@5.11.1
location: gnu/packages/kde-frameworks.scm:316:2
homepage: https://community.kde.org/Frameworks
license: LGPL 2.1+, LGPL 3+
synopsis: QML wrapper for BlueZ  
description: bluez-qt is a Qt-style library for accessing the bluez Bluetooth
+ stack.  It is used by the KDE Bluetooth stack, BlueDevil.
relevance: 4

name: qtconnectivity
version: 5.11.1
outputs: out
systems: x86_64-linux i686-linux armhf-linux aarch64-linux
dependencies: bluez@5.50 perl@5.26.1 pkg-config@0.29.2 qtbase@5.11.1
+ qtdeclarative@5.11.1
location: gnu/packages/qt.scm:918:2
homepage: https://www.qt.io/
license: LGPL 2.1, LGPL 3
synopsis: Qt Connectivity module  
description: The Qt Connectivity modules provides modules for interacting with
+ Bluetooth and NFC.
relevance: 2

name: modem-manager
version: 1.4.14
outputs: out
systems: x86_64-linux i686-linux armhf-linux aarch64-linux mips64el-linux
dependencies: dbus@1.12.6 glib@2.56.0 gobject-introspection@1.56.0
+ intltool@0.51.0 libgudev@230 libmbim@1.16.2 libqmi@1.20.0 pkg-config@0.29.2
+ polkit@0.115 vala@0.36.3
location: gnu/packages/freedesktop.scm:836:2
homepage: https://www.freedesktop.org/wiki/Software/ModemManager/
license: GPL 2+
synopsis: Mobile broadband modems manager  
description: ModemManager is a DBus-activated daemon which controls mobile
+ broadband (2G/3G/4G) devices and connections.  Whether built-in devices, USB
+ dongles, bluetooth-paired telephones, or professional RS232/USB devices with
+ external power supplies, ModemManager is able to prepare and configure the
+ modems and setup connections with them.
relevance: 2

name: hidapi
version: 0.8.0-rc1
outputs: out
systems: x86_64-linux i686-linux armhf-linux aarch64-linux mips64el-linux
dependencies: autoconf@2.69 automake@1.16.1 eudev@3.2.5 libtool@2.4.6
+ libusb@1.0.22 pkg-config@0.29.2
location: gnu/packages/libusb.scm:374:2
homepage: http://www.signal11.us/oss/hidapi/
license: GPL 3, Modified BSD, non-copyleft
synopsis: HID API library  
description: HIDAPI is a library which allows an application to interface with
+ USB and Bluetooth HID-Class devices.
relevance: 2

name: connman
version: 1.36
outputs: out
systems: x86_64-linux i686-linux armhf-linux aarch64-linux
dependencies: dbus@1.12.6 glib@2.56.0 gnutls@3.5.18 iptables@1.6.2
+ openconnect@7.08 openvpn@2.4.6 pkg-config@0.29.2 polkit@0.115 ppp@2.4.7
+ python2@2.7.14 readline@7.0.3 vpnc@0.5.3 wpa-supplicant@2.6
location: gnu/packages/connman.scm:44:2
homepage: https://01.org/connman
license: GPL 2
synopsis: Connection management daemon  
description: Connman provides a daemon for managing Internet connections.  The
+ Connection Manager is designed to be slim and to use as few resources as
+ possible.  It is fully modular system that can be extended through plug-ins.
+ The plug-in approach allows for easy adaption and modification for various use
+ cases.  Connman implements DNS resolving and caching, DHCP clients for both
+ IPv4 and IPv6, link-local IPv4 address handling and tethering (IP connection
+ sharing) to clients via USB, ethernet, WiFi, cellular and Bluetooth.
relevance: 2