Incorporate Peripheral Status (in General) into System Status Area
Feature summary
The System Status Area includes indicators for power/battery and for Bluetooth. However, it does not include information on the power/battery status of peripherals, just the main computing device itself. #3041 requests power/battery status for Bluetooth devices to be incorporated into the System Status Area, but Bluetooth devices are not the only class of peripherals that run off batteries.
The most common additional class of battery-powered wireless peripherals is probably Logitech's "Unifying" wireless I/O devices, which use an alternative (though documented) communication protocol. Presently, the third-party GTK application Solaar provides status and diagnostic information on Logitech "Unifying" devices in a manner similar to that of Bluetooth devices. However, Solaar creates an additional Status Icon outside of GNOME's System Status Area and does not in any way coordinate with GNOME's integrated Status Area interface, and Solaar confusingly uses the same icons for peripheral device power status as GNOME uses for the system power status. Additionally, the Solaar maintainers seem somewhat hostile towards GNOME's development trajectory.
How would you like it to work
In addition to providing power/battery information on Bluetooth devices as requested in #3041, the GNOME System Status Area should provide status information on all applicable peripherals, in particular those with power/battery status.
Additionally, GNOME Control Center should provide functionality for Logitech "Unifying" devices in a manner consistent with the functionality provided for Bluetooth devices. (This is, however, a separate issue.) Yes, Logitech's "Unifying" wireless protocol is proprietary. It is, however, extremely widely used, and it has been reverse-engineered and documented.
Relevant links, screenshots, screencasts etc.
Solaar's codebase can be found on GitHub.
In the below screenshot, the Solaar battery icon can be seen immediate to the left of the System Status Area group of icons:
To the extent that the group of icons in the System Status Area is extensible, it could incorporate icons for peripheral status. Alternately, if including the status of every peripheral threatens to overcrowd the top bar, the status of applicable peripherals could be included in the System Status dropdown, i.e. below the network status shown. (The computer this screenshot came from is a desktop with no internal battery, and it does not have a WiFi or Bluetooth NIC at the moment.)