Which version of GLES is supported?

[hajimehoshi]

• The package name is gles2.
• The build tag name is gles2.
• -l specifies GLES2

However,

• The gles2 package tries to load glBindTransformFeedback but this is not defined in GLES 2. This fails to launch.
• There is a commit to support GLES 3.

So, does go-gl support GLES2, or only 3? I'm confused.