In various places we have

namespace Foo {
...
} // Foo

in others we have

namespace Bar {
...
} // namespace Bar

This would be best to make consistent. In recent versions of clang-format (https://clang.llvm.org/docs/ClangFormatStyleOptions.html) this can be enforced automatically with the FixNamespaceComments option. The version in the Docker CI image is too old, so we need to upgrade this first.