GNU/Linux Ubuntu 18.04 Installing SeaMonkey – Step by step Guide
How to Install Mozilla SeaMonkey on Ubuntu 18.04 Bionic LTS 64-bit GNU/Linux desktop.
And Seamonkey for Ubuntu 18.04 includes an Internet Browser, eMail & Newsgroup Client, HTML Editor, IRC Chat and Web Development Tools.
Finally, the SeaMonkey Project is a Community Effort to Develop the SeaMonkey All-in-one Internet Application Suite.