The SAML Message Decoder is a Chrome extension that helps you debug and troubleshoot your SAML (Security Assertion Markup Language) based Single Sign-On (SSO) or Single Logout (SLO) implementations. It collects and displays SAML messages in easily readable XML format, allowing you to see what happened and solve authorization issues. The extension also offers additional features such as copying messages to the clipboard and exporting messages to a .json file for analysis.