Webscripts are functional modules in the Alfresco, which can just show some informations or also make some things inside the Alfresco (eg. run workflow, working with files, users, groups, or other entities).
Every webscripts has two main parts- code (.js, .java) and Freemaker template (.ftl)
Webscript can have also additional .properties file with text strings used in. Parts are paired in the context.xml file (Spring framework logic).
It's binded to any URL described in this file.