The direct link to the .js file on github is wrong. The second link in the Downloading section should be https://raw.githubusercontent.com/eclipse/paho.mqtt.javascript/master/src/paho-mqtt.js
The issues link is labelled incorrectly, it says https://github.com/eclipse/paho.mqtt.java/issues when it should say https://github.com/eclipse/paho.mqtt.javascript/issues
On https://www.eclipse.org/paho/clients/js/ the following need updating:
The direct link to the .js file on github is wrong. The second link in the Downloading section should be
https://raw.githubusercontent.com/eclipse/paho.mqtt.javascript/master/src/paho-mqtt.js
The issues link is labelled incorrectly, it says
https://github.com/eclipse/paho.mqtt.java/issues
when it should sayhttps://github.com/eclipse/paho.mqtt.javascript/issues