The overlay options in the image/uv editor is hidden in a side panel. Sometimes this panel is even hidden, while still useful.
The goal of this task is to introduce an overlay pop-over just like the overlay-popover of the 3d viewport.
* Popover has
** UV Stretching (only available in the UV mode, when active object mode is a mesh and in OB_EDIT mode)
** Display As (only available in the UV mode, when active object mode is a mesh and in OB_EDIT mode)
** Show Modified (only available in the UV mode, when active object mode is a mesh and in OB_EDIT mode)
** Show UV Edges (including opacity slider; available UV, View, Paint, when active object mode is a mesh and in OB_EDIT mode)
Like the 3d viewport, there will be a editor toggle to enable/disable the overlays