Only the given architectures are considered.
This reduces the amount of computing required when updating the database from Debian repositories. And it probably limits the packages to those being availble on the more popular desktop architectures like amd64 and i386.
Screenshots/thumbnails should be delivered statically from a front-end
web server. This introduces the "images_path_prefix" configuration
variable that makes the URL path configurable that is used to load
screenshots.