windows.md §7 weighed the Windows leg against the desktop leg in CPU
time only. What actually stopped a release was disk: the one 99 GB disk
is shared with the container images, v0.18.0's desktop run ended at
92 GB used, and v0.18.1's release build ran out, which is why that tag
has no release page. §7 now gives those figures, says what the desktop
leg deletes before its release build since 209ae361 and why that costs
the cache nothing, and names a second target's cache as the first thing
to check if a leg runs out again.