Pop!_Planet is still very much under development. Data for the wiki is being sourced from the Arch Linux and Ubuntu wikis, along with a bunch of completely unique content specific to Pop!_OS, and sourcing, converting and updating that content takes time; please be patient. If you can't find what you're looking for here, check the Arch Linux and Ubuntu wikis.
This is a simple Pop-inspired theme for Mattermost. To install, simply copy the block of code from the linked GitLab snippet and paste it under Account Settings -> Display -> Theme on Mattermost. Enjoy!