MAC spoofing failure notification should point to the corresponding documentation
It was implemented initially, and then the move to Wheezy made the link
invisible (tails/tails#7249), and for Jessie tails/tails#7989 [lead us to remove
it](https://tails.boum.org/blueprint/desktop_notifications/). It would
be great to tell the user what to do when MAC spoofing fails.
**Update**: on Bookworm, it's easier to fix that with `notify-send --action` (https://gitlab.tails.boum.org/tails/tails/-/issues/5856#note_222721).
As the blueprint linked above points out:
- a desktop notification may not be the best way to convey this
message;
- a process started in the background in a udev hook may not be the
best way to trigger that notification.
So this needs both UX and implementation research, quite possibly done
together (this is a corner case, and we don’t want to design something
perfect that’s so hard to implement that it’ll never be done).
# Proposed design
## Interface disabled
Using `notify-send`:
notify-send --action="Learn About MAC Address Anonymization" \
--icon=network-wireless-offline \
"Wi-Fi Disabled" \
"MAC address anonymization failed for your Wi-Fi interface, so it is temporarily disabled.\n \
\n \
You might prefer to restart Tails and disable MAC address anonymization."

Being able to differentiate different cases would make the notification much easier to interpret for users in the most common case (no Wi-Fi):
- If failure on the only Wi-Fi card
Wi-Fi Disabled
MAC address anonymization failed for your Wi-Fi interface,
so it is temporarily disabled.
- If failure on one of several Wi-Fi cards
Wi-Fi Interface Disabled
MAC address anonymization failed for one of your Wi-Fi interfaces,
so it is temporarily disabled.
{nic}: {nic_name}
- If failure on the only Ethernet card
Wired Internet Disabled
MAC address anonymization failed for your wired interface,
so it is temporarily disabled.
- If failure on one of several Ethernet cards
Wired Interface Disabled
MAC address anonymization failed for one of your wired interfaces,
so it is temporarily disabled.
{nic}: {nic_name}
## All network disabled
- If failure on the only interface
All Networking Disabled
MAC address anonymization failed for your network interface.
The error recovery also failed, so all networking is disabled.
- If failure on one of several interface
All Networking Disabled
MAC address anonymization failed for one of your network interfaces.
The error recovery also failed, so all networking is disabled.
{nic}: {nic_name}
issue