Hi Elyess,
I’m still pretty new to Looker, but I use Content Validator (nearly) every day to check for broken content. It’s under the Develop menu and will show you what is wrong and provide you with the option to remove or replace the broken content, whether a field, view, explore, or model.
I just edited this as I realize this won’t capture source changes. Pardon my newbee-ness.