.PLSK File Extension
File TypeMessenger Plus! Live Skin Pack
File format categories include Binary, Text, XML, and Zip. The format of this file type has not been determined.
What is a PLSK file?
Skin that can be applied to the interface of Windows Live Messenger (WLM), a popular instant messaging program for Windows; requires the Messenger Plus! Live add-on, which provides extra functionality for WLM.
NOTE: Windows Live Messenger was discontinued in 2013 and has moved to Skype.