There are 17 repositories under webmail topic.
Monorepo hosting the proton web clients
Simple, modern & fast web-based email client
AfterLogic WebMail Lite PHP. Fast and easy-to-use webmail front-end for your existing IMAP mail server, Plesk or cPanel.
An ad-hoc disposable temporary mail server. Create and use ad hoc disposable mailboxes for testing or any other purpose.
Open-source webmail script for existing IMAP server
Web based groupware server written in PHP, forum at https://help.egroupware.org/
Isotope Mail Client
poste.io mail server, but with IP management and custom webmail plugins
🌰️🐿️ SquirrelMail GitHub Repository (PHP 7-OK!)
Mail Toaster 6
Webmail front-end for existing mail server, with personal calendar, contacts, and mobile sync.
A secure and PGP enabled webmail module for Phosphorus Five
Rainloop package for YunoHost
Self-hosted webmail client greatly inspired by Google Inbox (Backend)
Host your own rainloop using docker 🐳📧
Some exploit scripts for Webmail
Roundcube package for YunoHost
Dark theme for Roundcube as used by Courvix Mail