lamejs (LAME MP3 encoder, JavaScript port) 1.2.1 is free software under the GNU Lesser General Public License, version 3 (LGPL-3.0).
Palz Tools serves it unmodified as a separate file and loads it at runtime; it is not part of the site's own code.
Source code: https://github.com/zhuker/lamejs/tree/1.2.1 (npm: lamejs@1.2.1)
LAME project: https://lame.sourceforge.io/
Licence texts (LGPL-3.0 and the GPL-3.0 it refers to): COPYING.txt in this folder.