* The system sees the opening quote mark, and is therefore alerted to look for the closing quote at the end of the keyword phrase. (After widgets, in other words.)
* When it doesn't find the closing quote at the end of the word widgets, it assumes a 'mistake was made'.
* It then converts both quote marks to extra spaces.
* This gives you a broad match with extra spaces before the words new and widgets
* It ignores the spaces, and gives you a broad match as follows:
new work widgets
To prove this out, you could actually create an ad group with that as the only keyword. Let all the servers update, and try searching on 'york new widgets' or similar. If it is in fact a broad match, your ad would show.
(BTW, trying things like this is a good way to test theories, and see what happens in the real world.)
Once finished with the experiment, delete the Ad Group. Unless it is converting of course! ;)
AWA