The tar archive for branding files (iceweasel_52.0-1.branding.tar.xz) is actually a plain tar archive despite the xz file extension. While this doesn't affect the resulting Parabola package, it may confuse some tools¹ if the file is used elsewhere. It also increased the size of the archive by 10 times compared to the previous version.

[1]: For example, Gentoo's Portage will fail to automatically extract the file if it were used in an ebuild.