Last tested: May 2020
The content validator checks to see which of your Looks and dashboard tiles are broken by LookML changes.
DOES
Replace models, explores, views, fields, fields used in table calculations and custom fields
Remove models, explores, views and fields
Check lookless tiles (Looker 5.10+)
Validates against the mode you're in (dev : active branch or prod) however changes are applied globally
Give the ability to delete broken looks/tiles
Check personal spaces
Check look filters
Check dashboard filters (Looker 6.10+)
Allow calling through the API (https://docs.looker.com/reference/api-and-integration/api-reference/v3.1/content#validate_content)
DOES NOT
Remove fields used in table calculations and custom fields
Check LookML dashboards (LookML validator does this)
Check a subset of content
Check Trash (Looker 4.12+)
Check content you don't have access to
Time out after a certain period of time. (However, restarting the Looker instance does kill the Content Validator.)
Way more info in Docs.
This content is subject to limited support.
Validates against the mode you're in (dev : active branch or prod) however changes are applied globally
Would be great if this part were specifically stated in the Looker documentation here
From the current doc, it gives the impression that there is a separation between dev mode and production when a change hasn’t been pushed to production.