I wonder why this doesn't work on Manjaro.

Because Manjaro is a different Linux distribution from Arch Linux, and have a different selection of packages.

> without a network

> pacman -S arch-wiki-docs elinks

does pacman install docs and elinks without network?

interesting

I am sure OP meant to run this once when you have an internet connection after which you will be able to view the docs offline.

I'm sure you understood what I meant, but if you want to be literal, then yes: you can also install packages with pacman while offline, if you have downloaded the packages first.

This command downloads the packages without installing them:

    pacman -Sw elinks arch-wiki-docs