Permission problem with Swift 3.0 Preview 1 on Ubuntu 14.04

I downloaded and installed Swift 3.0 Preview 1 on Ubuntu 14.04, following the instructions in - Download Swift.

For some reason, all files in the
directory of the archive have mode "-rw-r-----", i.e. they are not world-readable.

As a consequence, swift cannot be executed as a "normal" user:

$ swift-3.0-PREVIEW-1-ubuntu14.04/usr/bin/swift
Welcome to Swift version 3.0 (swift-3.0-PREVIEW-1). Type :help for assistance.
1> 1+2
error: cannot open file '/usr/local/src/Swift/swift-3.0-PREVIEW-1-ubuntu14.04/usr/lib/swift/CoreFoundation/module.modulemap': Permission denied


That can be fixed easily with "chmod -R o+r ...", but is there a particular reason for this restriction? Is is worth a bug report?

Regards, Martin