Flatpak build often breaks due to upstream dependency changes
It happened at least twice (!1600 (merged), #2287 (closed)) that the flatpak build breaks due to changes in the dependencies' repos. Yet, it breaks only to those who didn't have dependencies cache, i.e. those who just cloned the repo. This happens because the flatpak build specifies modules' sources to be downloaded from the main branch of a git repository. Not every repository manages to keep main unbreakable.