With PORTAGE_COMPRESS="lzma" the info-files will get compressed with lzma, but although it is possible to view them with "info" it is not possible to view these files currently with pinfo. The same will happen with the successor format PORTAGE_COMPRESS="xz" (this can currently be tested only with the patch from bug 269742). It is almost trivial to patch pinfo such that both formats are supported.
Created attachment 191278 [details, diff] Patch against pinfo-0.6.9 to support lzma and xz compression
Fixed in 0.6.9-r1 in June. :)