GitHub and GitLab are pretty similar but do have some differences. One of them springs from the fact that source code systems such as Git traditionally didn't cater much for the storage of large binary files. There have always been other ways, such as storing file paths to a file server in plain text files.
But what if you actually have files that are, in a sense, equivalent to source files, except that they are binary, and you still want to version them? Such file types might include image files, video files, and audio files. Modern websites make increasing use of media files, and this area has typically been the domain of content management systems (CMSes). CMSes, however nice they might be, have disadvantages compared to DevOps flows, so the allure of storing media files in your ordinary source handling system is strong. Disadvantages of CMSes include...