[1.57] turtle.detect() Block ID Detection setting.

"Turtles are intended to be blind.
As such, they can only detect the presense of items, and comparing the item to another item in its inventory.
Directly detecting block IDs would break the fourth wall."
Lyqyd

(original version)
And I agree. However, an extra line in the settings file to enable this options would be nice. Maybe you do want this option enabled, maybe you think it's cheating. I wouldn't recommend it for single player either, but maybe it is an idea for people playing in creative mode, or people programming a real life robot.
That's why I am suggesting an option to add Block ID detection, just like the http- and CommandBlock option.

The developers have stated that it isn't going to happen.

It's also on the Things Not to Suggest list, for the above reason.