<model-viewer> is an open-source web component developed by Google and maintained through GitHub. <model-viewer> aims at putting 3D content on the web easily with a few lines of HTML code. This was first introduced with Chrome 72 in July 2019 and enables users to view 3D in the browser and mobile devices.
GitLab is a web-based DevOps lifecycle tool that provides a Git-repository manager providing wiki, issue-tracking and continuous integration and deployment pipeline features, using an open-source license.
Unpkg is a content delivery network for everything on npm.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.