The designs for the Page & Categories and Other tabs require page and file size, respectively, for results. We have access to those sizes in bytes but the methods for formatting these results and adding language-specific units currently exist on the backend (see the Language::formatSize). We either need to reimplement this functionality on the client side so we can process what we're getting back from the API, or we need to preprocess results to include the human-readable size string.
Pages & Categories tab:
Other tab: