LWJGL tex.getTextureData() Is this a copy?

The title should be self explanatory. Does the method getTextureData() from the Texture class return the byte array that is stored within an OpenGL texture, or is it just a copy? I’m alright if either are the case, but I just want to know. If you’re curious, I’m using it for my Button class. The class ignores mouse clicks and rollovers if a pixel has an alpha of 0.