Download Mudlet – it’s free and opensource :)
Mudlet 3.13.0 (Linux) (29.3 MiB)
This is a portable version of Mudlet - after downloading, extract the launcher somewhere permanent and use it to launch Mudlet.
Interested in installing Mudlet on ChromeOS? Beta instructions are available here!
Mudlet 3.13.0 (Source code) (5.2 MiB)
Mudlet wiki has information on how to compile Mudlet on different operating systems.
Older installers for Mudlet are available here.
Source code for the latest Mudlet (browse on Github) is also available via git:
git clone --recursive --branch master https://github.com/Mudlet/Mudlet.git