Configurable new user temp/QWK archive type
Right now, if there are any compressible file types configured, the first one listed is the new-user-default (even if they don't meet the access requirements (!)). If none are listed, "zip" is chosen (the first element of the supported_archive_formats array). It used to be just hard-coded to "ZIP" always.
Instead, it's probably best to just allow the sysop to set the desired new-user-default temp-archive format as a string (with a default of "zip").