CRM Dev Tool is a great tool which reduces a lot of time of dynamics 365 professionals in their day to day activities. It is an add on to google chrome and easy to use. Just to list a few usages:
- Form information (entity name, Id, entity type code, dirty fields in the form etc.)
- Show hidden attributes in a form, show schema names of all fields without opening the form customisation, enable all fields in the form.
- View Current User details (user Id, security roles etc.)
- Execute Fetch XML queries and view the results.
More details available on http://blog.sonomapartners.com/2014/01/introducting-dynamics-crm-devtools.html