It seems the loolwsd package of the new Debian 10 repositories are currently build against the following transitional package: apt info loolwsd Depends: *long_dep_list*, libgl1-mesa-glx, *long_dep_list* https://packages.debian.org/buster/libgl1-mesa-glx For Debian 10/Buster the following is the replacement for this transitional package: https://packages.debian.org/buster/libglx-mesa0 which could be used as a dependency instead so that Debian 10 users are able to remove this transitional package.
The next generation of CODE packages will not depend on Mesa at all. So I'd rather not fix this for the CODE 4.0.x series, that will become obsolete soon.