Draft: 2.80.2

As with 2.80.1, we should let the version in unstable migrate to testing before uploading this, unless there is another showstopper issue preventing migration, in which case we might as well take the opportunity to update to 2.80.2 as well.

The most important parts of 2.80.2 are already fixed in Debian's 2.80.1-1, which I prepared in parallel with upstream doing 2.80.2. I have not assessed whether the same is true in Ubuntu; I suspect it is not.

Note that this contains packaging tweaks to compensate for upstream changes in the documentation.