Meson build requires networking to build docs
Building with Meson needs network access to run this command. With the autotools build, that was only run if you were building with maintainer mode.
This may cause surprises or issues for distribution packagers where network access is restricted or not available. On Solus, for instance, our package build system disables networking by default in the build environment, though we can turn it back on if a package really requires it, and has a good reason.