Spec 1.5

EGLContext is an opaque type representing a client API context.
The definition of contexts depends on the client API,
but usually represents the state vector of an abstract machine
describing the client API and allows executing client API commands with respect to that state vector.

EGLImage is an opaque type representing handles to EGLImage objects.
EGLSurface is an opaque type representing a drawing surface which client APIs can render content into.
EGLSync is an opaque type representing handles to sync objects.
EGLTime is a 64-bit unsigned integer type representing a timeout interval in nanoseconds for eglClientWaitSync.

EGLDisplay represents the abstract display on which graphics are drawn.

All modifications to shared context state as a result of executing glBindBuffer are atomic.
Also, a buffer object will not be deleted while it is still bound to any context.