Last tested: Jul 1, 2018
The long url of a look is of the form:
This means a look will break or change in the following situations:
-model is changed or deleted such that
MODEL NAME is no longer valid
-explore is changed, moved or deleted such that
EXPLORE NAME is no longer valid
-field is changed or deleted such that a field name is no longer valid.
This means you can move a model to a new project, for example, and the look will not break as long as the explore and model have the same name.