User-agent:
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0
so, having figured out that something somewhere ran out of space, what
can I do about it? Which of the many partitions is it complaining about,
and what can I delete? Can I resize the partitions to give up some user
data space for whatever the system image thing needs?