Package: claws-mail

"claws-mail" package binaries on CentOS:

/usr/bin/claws-mail /usr/bin/sylpheed-claws

You may install this package on CentOS with yum install claws-mail

"claws-mail" package binaries on Debian:

/usr/bin/claws-mail

You may install this package on Debian with apt-get install claws-mail