$ gpg --recv-keys 0x676041BA
[...]
$ gpg --list-sigs 0x676041BA
pub   1024D/676041BA 2008-06-13
uid                  Cygwin <cygwin@cygwin.com>
sig 3        676041BA 2008-06-13  Cygwin <cygwin@cygwin.com>
sig          6A388C3E 2008-06-13  Dave Korn (release signing key) <dave.korn.cygwin@gmail.com>
sig          084C1C68 2015-10-06  [User ID not found]
sig          5685D1E8 2013-04-11  [User ID not found]
sig          C5B3322D 2014-03-13  [User ID not found]
sig          D054015D 2015-07-02  [User ID not found]
sig          3664A7F2 2015-03-23  [User ID not found]
sig          FDE2759C 2012-08-10  [User ID not found]
sig          9D17999F 2012-08-10  [User ID not found]
sig          94C09C7F 2015-01-08  [User ID not found]
sig          99C8A397 2015-07-26  [User ID not found]
sig 3        85F0ED85 2011-04-04  [User ID not found]
sub   1024g/A1DB7B5C 2008-06-13
sig          676041BA 2008-06-13  Cygwin <cygwin@cygwin.com>