The current EL artifacts can be downloaded from Maven Central repositories.
The group ID and the artifact ID are javax.el and javax.el-api for the api, and org.glassfish.web and javax.el for the implementation. They all have versions 2.2.x.
Expression Language, referred to as EL, was first introduced in JSTL 1.0, and later included in JSP 2.0. A variant of the EL was used in JSF 1.0. In JSP 2.1, JSF 1.2 and JSTL 1.2, a unified EL was defined.
The JSP, JSTL, and Faces expert group felt that EL is useful beyond their specifications. JSP 2.1 MR includes features that enable current EL to be a pluggable module.
The official specification and javadocs can be downloaded from JCP JSR 245 site. Javadocs for the EL API (javax.el package) can also be found from Java EE API.