https://javierlona.com/installing-mailcatcher-for-development-email/
Installing MailCatcher for Development Email
MailCatcher is excellent for testing your web apps email functionality on a local development environment.
installingmailcatcherdevelopmentemail
https://packages.debian.org/source/testing/mailcatcher
Debian -- Details of source package mailcatcher in forky
debiandetailssourcepackagemailcatcher