Mypal
Mypal is a discontinued fork of Moonchild Productions' Pale Moon browser, targeted primarily at Windows XP. It was developed by Feodor2.
The latest version was 29.3.0 based on the respective version of Pale Moon. Like all browsers based on UXP, it uses the Goanna rendering engine, a fork of Gecko.
Use on CollabVM
Mypal was the default browser on VM2, from March 2021 to April 25th 2022, when it was replaced with Mypal 68.
Discontinuation
Due to the Pale Moon developers disliking the creation of forks for the use on Windows XP, and older operating systems in general, they decided all of a sudden that the browser was no longer in line with the MPL (Mozilla Public License), and therefore created a GitHub issue to complain about it. Many things happened, but Feodor was essentially bullied into discontinuing the browser. The final version can still downloaded from its website, and a mirror of the source code can be found here.