The acronym EGL is an initialism, which starting from EGL version 1.2 refers to Khronos Native Platform Graphics Interface. Prior to version 1.2, the name of the EGL specification was OpenGL ES Native Platform Graphics Interface. X.Org development documentation glossary defines EGL as "Embedded-System Graphics Library".
Wayland clients use EGL to directly draw into the framebuffer. The display server sits between the kernel (here: Linux kernel) and its clients. It communicates with its clients over a given protocol.
The free implementations of the Wayland (display server protocol) rely upon the Mesa implementation of EGL. A special library called libwayland-EGL was written to accommodate the access to the framebuffer.
The BlackBerry 10 and BlackBerry Tablet OS mobile device operating system uses EGL for 3D graphics rendering. Both support EGL version 1.4.
The Android mobile device operating system uses EGL for 3D graphics rendering.
The Wayland display server protocol uses EGL. It is implemented in a way that Wayland clients will draw directly to the framebuffer using EGL.
Mesa 3D has an implementation of EGL formerly known as Eagle.