libesmtp-dev

Package contains libraries, required by other applications as dependencies. Do not install separately.

LibESMTP SMTP client library development files
LibESMTP is a library to manage posting (or submission of) electronic
mail using SMTP to a preconfigured Mail Transport Agent (MTA) such as
Exim. It may be used as part of a Mail User Agent (MUA) or another
program that must be able to post electronic mail but where mail
functionality is not the program's primary purpose.