I’ve never heard of that type before and I wasn’t able to find anything with google.
Furthermore more, the lack of company information (address, company registration nr etc) and the fact that it’s not clear where the servers are located geographically makes me a bit hesitant.
When tasked to do some e-mail template development at work without access to a mail server I developed a small cli tool[1] that converts HTML to EML so I could send it as an attachment to the test devices.
Mousable is an open-source menu bar app that lets you fully control the cursor, clicks, scrolling, and dragging using only the keyboard.
Built for keyboard-first workflows, ergonomics, and flow.
Based on the open source (unfortunately no longer maintained) Windows version
Feedback welcome: https://github.com/rootdevelop/mousable-macos