Lzip offers better compression ratios and archival features compared to more common .gz or .xz formats, and is being used by some software to package their distfiles, e.g. archivers/zutils, astro/gnuastro,sysutils/ddrescue, for which we either have to use bigger .tar.gz distfile, or set EXTRACT_DEPENDS=lzip:archivers/lzip and then manually extract the distfile.
Proposed patch adds .tar.lz suffix support to our framework, since BSD tar(1) natively supports it.