The Network Tab shows a table of every resource that has been requested since Web Inspector was opened.
The Timelines Tab contains all of the performance profiling and introspection tools provided by Web Inspector, organized into different timelines each with their own area of interest and specialized interface.
Web Inspector Open / Close Web Inspector ⌥ ⌘ I Connect / Disconnect Web Inspector ⌥ ⇧ ⌘ I Go to file or resource… ⇧ ⌘ O or ⌘ P Reload Reload inspected page ⌘ R Reload inspected page from origin ⌥ ⌘ R Appearance Docking Configuration Switch to previous docking configuration ⇧ ⌘ D Zoom Increase zoom ⌘ + or ⇧ ⌘ + Decrease zoom ⌘ – or ⇧ ⌘ – Reset […]
The Sources Tab is the one-stop shop for all things related to the inspected target’s resources, including dynamic resources from things like XMLHttpRequest or fetch.
As web development workflows have gotten more complicated, it’s become increasingly difficult to make quick changes to a resource and upload it to a server to test.