Recently (2015-04-06) they put a new cert on https://easylist-downloads.adblockplus.org
Some utilities (like wget) do not trust it.
# wget https://easylist-downloads.adblockplus.org/easylist.txt
--2015-04-08 13:53:13-- https://easylist-downloads.adblockplus.org/easylist.txt
Resolving easylist-downloads.adblockplus.org (easylist-downloads.adblockplus.org)... 78.46.70.139, 88.198.15.197, 2a01:4f8:130:9384::2, ...
Connecting to easylist-downloads.adblockplus.org (easylist-downloads.adblockplus.org)|78.46.70.139|:443... connected.
ERROR: The certificate of `easylist-downloads.adblockplus.org' is not trusted.
ERROR: The certificate of `easylist-downloads.adblockplus.org' hasn't got a known issuer.
My guess is that it does not have all the intermediate certs listed since COMODO, AddTrust and UTN root certs are installed by default.
https://bugs.debian.org/cgi-bin/bugrepo ... bug=742810
easylist certificate issues
You might want to report that here: https://issues.adblockplus.org/